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data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Thermal_cycloadditions_and_their_stereochemistry" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Thermal_cycloadditions_and_their_stereochemistry"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Thermal cycloadditions and their stereochemistry</span> </div> </a> <ul id="toc-Thermal_cycloadditions_and_their_stereochemistry-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Photochemical_cycloadditions_and_their_stereochemistry" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Photochemical_cycloadditions_and_their_stereochemistry"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Photochemical cycloadditions and their stereochemistry</span> </div> </a> <ul id="toc-Photochemical_cycloadditions_and_their_stereochemistry-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Types_of_cycloaddition" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Types_of_cycloaddition"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Types of cycloaddition</span> </div> </a> <button aria-controls="toc-Types_of_cycloaddition-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Types of cycloaddition subsection</span> </button> <ul id="toc-Types_of_cycloaddition-sublist" class="vector-toc-list"> <li id="toc-Diels-Alder_reactions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Diels-Alder_reactions"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Diels-Alder reactions</span> </div> </a> <ul id="toc-Diels-Alder_reactions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Huisgen_cycloadditions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Huisgen_cycloadditions"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Huisgen cycloadditions</span> </div> </a> <ul id="toc-Huisgen_cycloadditions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Nitrone-olefin_cycloaddition" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Nitrone-olefin_cycloaddition"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Nitrone-olefin cycloaddition</span> </div> </a> <ul id="toc-Nitrone-olefin_cycloaddition-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Cheletropic_reactions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Cheletropic_reactions"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Cheletropic reactions</span> </div> </a> <ul id="toc-Cheletropic_reactions-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Other" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Other"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Other</span> </div> </a> <ul id="toc-Other-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Formal_cycloadditions" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Formal_cycloadditions"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Formal cycloadditions</span> </div> </a> <button aria-controls="toc-Formal_cycloadditions-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Formal cycloadditions subsection</span> </button> <ul id="toc-Formal_cycloadditions-sublist" class="vector-toc-list"> <li id="toc-Iron-catalyzed_2+2_olefin_cycloaddition" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Iron-catalyzed_2+2_olefin_cycloaddition"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Iron-catalyzed 2+2 olefin cycloaddition</span> </div> </a> <ul id="toc-Iron-catalyzed_2+2_olefin_cycloaddition-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button 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Available in 22 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-22" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">22 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A5%D8%B6%D8%A7%D9%81%D8%A9_%D8%AD%D9%84%D9%82%D9%8A%D8%A9" title="إضافة حلقية – Arabic" lang="ar" hreflang="ar" data-title="إضافة حلقية" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Cicloaddici%C3%B3" title="Cicloaddició – Catalan" lang="ca" hreflang="ca" data-title="Cicloaddició" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Cykloadice" title="Cykloadice – Czech" lang="cs" hreflang="cs" data-title="Cykloadice" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Cykloaddition" title="Cykloaddition – Danish" lang="da" hreflang="da" data-title="Cykloaddition" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Cycloaddition" title="Cycloaddition – German" lang="de" hreflang="de" data-title="Cycloaddition" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Cicloadici%C3%B3n" title="Cicloadición – Spanish" lang="es" hreflang="es" data-title="Cicloadición" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AD%D9%84%D9%82%D9%87%E2%80%8C%D8%B2%D8%A7%DB%8C%DB%8C" title="حلقه‌زایی – Persian" lang="fa" hreflang="fa" data-title="حلقه‌زایی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Cycloaddition" title="Cycloaddition – French" lang="fr" hreflang="fr" data-title="Cycloaddition" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Sikloadisi" title="Sikloadisi – Indonesian" lang="id" hreflang="id" data-title="Sikloadisi" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Cicloaddizione" title="Cicloaddizione – Italian" lang="it" hreflang="it" data-title="Cicloaddizione" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Cycloadditie" title="Cycloadditie – Dutch" lang="nl" hreflang="nl" data-title="Cycloadditie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E7%92%B0%E5%8C%96%E4%BB%98%E5%8A%A0%E5%8F%8D%E5%BF%9C" title="環化付加反応 – Japanese" lang="ja" hreflang="ja" data-title="環化付加反応" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Sykloaddisjon" title="Sykloaddisjon – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Sykloaddisjon" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Cykloaddycja" title="Cykloaddycja – Polish" lang="pl" hreflang="pl" data-title="Cykloaddycja" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Cicloadi%C3%A7%C3%A3o" title="Cicloadição – Portuguese" lang="pt" hreflang="pt" data-title="Cicloadição" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Cicloadi%C8%9Bie" title="Cicloadiție – Romanian" lang="ro" hreflang="ro" data-title="Cicloadiție" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A0%D0%B5%D0%B0%D0%BA%D1%86%D0%B8%D0%B8_%D1%86%D0%B8%D0%BA%D0%BB%D0%BE%D0%BF%D1%80%D0%B8%D1%81%D0%BE%D0%B5%D0%B4%D0%B8%D0%BD%D0%B5%D0%BD%D0%B8%D1%8F" title="Реакции циклоприсоединения – Russian" lang="ru" hreflang="ru" data-title="Реакции циклоприсоединения" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Cycloaddition" title="Cycloaddition – Simple English" lang="en-simple" hreflang="en-simple" data-title="Cycloaddition" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Sykloadditio" title="Sykloadditio – Finnish" lang="fi" hreflang="fi" data-title="Sykloadditio" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Cykloaddition" title="Cykloaddition – Swedish" lang="sv" hreflang="sv" data-title="Cykloaddition" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A6%D0%B8%D0%BA%D0%BB%D0%BE%D0%BF%D1%80%D0%B8%D1%94%D0%B4%D0%BD%D0%B0%D0%BD%D0%BD%D1%8F" title="Циклоприєднання – Ukrainian" lang="uk" hreflang="uk" data-title="Циклоприєднання" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a 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</div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Chemical reaction which forms a cyclic molecule</div> <p>In <a href="/wiki/Organic_chemistry" title="Organic chemistry">organic chemistry</a>, a <b>cycloaddition</b> is a <a href="/wiki/Chemical_reaction" title="Chemical reaction">chemical reaction</a> in which "two or more <a href="/wiki/Unsaturated_hydrocarbon" class="mw-redirect" title="Unsaturated hydrocarbon">unsaturated</a> molecules (or parts of the same molecule) combine with the formation of a cyclic <a href="/wiki/Adduct" title="Adduct">adduct</a> in which there is a net reduction of the <a href="/wiki/Multiplicity_(chemistry)#Molecules" title="Multiplicity (chemistry)">bond multiplicity</a>". The resulting reaction is a <a href="/wiki/Cyclization" class="mw-redirect" title="Cyclization">cyclization</a> reaction. Many but not all cycloadditions are <a href="/wiki/Concerted_reaction" title="Concerted reaction">concerted</a> and thus <a href="/wiki/Pericyclic" class="mw-redirect" title="Pericyclic">pericyclic</a>.<sup id="cite_ref-goldbook_1-0" class="reference"><a href="#cite_note-goldbook-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Nonconcerted cycloadditions are not pericyclic.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> As a class of <a href="/wiki/Addition_reaction" title="Addition reaction">addition reaction</a>, cycloadditions permit carbon–carbon bond formation without the use of a <a href="/wiki/Nucleophile" title="Nucleophile">nucleophile</a> or <a href="/wiki/Electrophile" title="Electrophile">electrophile</a>. </p><p>Cycloadditions can be described using two systems of notation. An older but still common notation is based on the size of linear arrangements of atoms in the reactants. It uses <a href="/wiki/Parentheses" class="mw-redirect" title="Parentheses">parentheses</a>: <span class="nowrap">(<i>i</i> + <i>j</i> + …)</span> where the variables are the numbers of linear atoms in each reactant. The product is a cycle of size <span class="nowrap">(<i>i</i> + <i>j</i> + …)</span>. In this system, the standard <a href="/wiki/Diels-Alder_reaction" class="mw-redirect" title="Diels-Alder reaction">Diels-Alder reaction</a> is a (4 + 2)-cycloaddition, the <a href="/wiki/1,3-dipolar_cycloaddition" class="mw-redirect" title="1,3-dipolar cycloaddition">1,3-dipolar cycloaddition</a> is a (3 + 2)-cycloaddition and <a href="/wiki/Cyclopropanation" title="Cyclopropanation">cyclopropanation</a> of a carbene with an alkene a (2 + 1)-cycloaddition.<sup id="cite_ref-goldbook_1-1" class="reference"><a href="#cite_note-goldbook-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>A more recent, IUPAC-preferred notation, first introduced by <a href="/wiki/Robert_Burns_Woodward" title="Robert Burns Woodward">Woodward</a> and <a href="/wiki/Roald_Hoffmann" title="Roald Hoffmann">Hoffmann</a>, uses <a href="/wiki/Square_brackets" class="mw-redirect" title="Square brackets">square brackets</a> to indicate the number of <i>electrons</i>, rather than carbon atoms, involved in the formation of the product. In the [<i>i</i> + <i>j</i> + ...] notation, the standard Diels-Alder reaction is a [4 + 2]-cycloaddition, while the 1,3-dipolar cycloaddition is also a [4 + 2]-cycloaddition.<sup id="cite_ref-goldbook_1-2" class="reference"><a href="#cite_note-goldbook-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Thermal_cycloadditions_and_their_stereochemistry">Thermal cycloadditions and their stereochemistry</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=1" title="Edit section: Thermal cycloadditions and their stereochemistry"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Thermal cycloadditions are those cycloadditions where the reactants are in the ground electronic state. They usually have (4<i>n</i> + 2) π electrons participating in the starting material, for some integer <i>n</i>. These reactions occur for reasons of <a href="/wiki/Orbital_symmetry" class="mw-redirect" title="Orbital symmetry">orbital symmetry</a> in a <a href="/wiki/Suprafacial" class="mw-redirect" title="Suprafacial">suprafacial</a>-suprafacial (<i>syn</i>/<i>syn</i> stereochemistry) in most cases. Very few examples of <a href="/wiki/Antarafacial" class="mw-redirect" title="Antarafacial">antarafacial</a>-antarafacial (<i>anti</i>/<i>anti</i> stereochemistry) reactions have also been reported. There are a few examples of thermal cycloadditions which have 4<i>n</i> π electrons (for example the [2 + 2]-cycloaddition). These proceed in a suprafacial-antarafacial sense (<i>syn</i>/<i>anti</i> stereochemistry), such as the cycloaddition reactions of <a href="/wiki/Ketene" title="Ketene">ketene</a> and <a href="/wiki/Allenes" title="Allenes">allene</a> derivatives, in which the <a href="/wiki/Orthogonal" class="mw-redirect" title="Orthogonal">orthogonal</a> set of <a href="/wiki/P_orbital" class="mw-redirect" title="P orbital">p orbitals</a> allows the reaction to proceed via a crossed <a href="/wiki/Transition_state" title="Transition state">transition state</a>, although the analysis of these reactions as [<sub>π</sub>2<sub>s</sub> + <sub>π</sub>2<sub>a</sub>] is controversial. Strained alkenes like <i>trans</i>-cycloheptene derivatives have also been reported to react in an antarafacial manner in [2 + 2]-cycloaddition reactions. </p><p><a href="/wiki/William_von_Eggers_Doering" title="William von Eggers Doering">Doering</a> (in a personal communication to <a href="/wiki/Robert_Burns_Woodward" title="Robert Burns Woodward">Woodward</a>) reported that <a href="/wiki/Fulvalene_(compound_class)" class="mw-redirect" title="Fulvalene (compound class)">heptafulvalene</a> and tetracyanoethylene can react in a suprafacial-antarafacial [14 + 2]-cycloaddition. However, this reaction was later found to be stepwise, as it also produced the Woodward-Hoffmann forbidden suprafacial-suprafacial product under kinetic conditions. <sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>Erden and Kaufmann had previously found that the cycloaddition of heptafulvalene and N-phenyltriazolinedione also gave both suprafacial-antarafacial and suprafacial-suprafacial products. <sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-halign-center" typeof="mw:File/Frameless"><a href="/wiki/File:14plus2.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/82/14plus2.png/400px-14plus2.png" decoding="async" width="400" height="161" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/82/14plus2.png/600px-14plus2.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/82/14plus2.png/800px-14plus2.png 2x" data-file-width="1906" data-file-height="769" /></a><figcaption></figcaption></figure> <div class="mw-heading mw-heading2"><h2 id="Photochemical_cycloadditions_and_their_stereochemistry">Photochemical cycloadditions and their stereochemistry</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=2" title="Edit section: Photochemical cycloadditions and their stereochemistry"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Cycloadditions in which 4n π electrons participate can also occur via <a href="/wiki/Photochemistry" title="Photochemistry">photochemical</a> activation. Here, one component has an electron promoted from the <a href="/wiki/HOMO" class="mw-redirect" title="HOMO">HOMO</a> (π bonding) to the <a href="/wiki/LUMO" class="mw-redirect" title="LUMO">LUMO</a> (π* <a href="/wiki/Antibonding" class="mw-redirect" title="Antibonding">antibonding</a>). Orbital symmetry is then such that the reaction can proceed in a suprafacial-suprafacial manner. An example is the <a href="/wiki/DeMayo_reaction" title="DeMayo reaction">DeMayo reaction</a>. Another example is shown below, the photochemical dimerization of <a href="/wiki/Cinnamic_acid" title="Cinnamic acid">cinnamic acid</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> The two <i>trans</i> <a href="/wiki/Alkene" title="Alkene">alkenes</a> react head-to-tail, and the isolated <a href="/wiki/Isomer" title="Isomer">isomers</a> are called <i><a href="/wiki/Truxillic_acid" title="Truxillic acid">truxillic acids</a></i>. </p> <dl><dd><figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:CinnamicAcidCycloAddition.png" class="mw-file-description" title="Cinnamic Acid CycloAddition"><img alt="Cinnamic Acid CycloAddition" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/53/CinnamicAcidCycloAddition.png/400px-CinnamicAcidCycloAddition.png" decoding="async" width="400" height="164" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/53/CinnamicAcidCycloAddition.png/600px-CinnamicAcidCycloAddition.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/53/CinnamicAcidCycloAddition.png/800px-CinnamicAcidCycloAddition.png 2x" data-file-width="1212" data-file-height="496" /></a><figcaption>Cinnamic Acid CycloAddition</figcaption></figure></dd></dl> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Bpe-resorcinol-cycloaddition.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c4/Bpe-resorcinol-cycloaddition.png/220px-Bpe-resorcinol-cycloaddition.png" decoding="async" width="220" height="169" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c4/Bpe-resorcinol-cycloaddition.png/330px-Bpe-resorcinol-cycloaddition.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c4/Bpe-resorcinol-cycloaddition.png/440px-Bpe-resorcinol-cycloaddition.png 2x" data-file-width="2475" data-file-height="1904" /></a><figcaption>Cycloaddition of <i>trans</i>-1,2-bis(4-pyridyl)ethene</figcaption></figure> <p><a href="/wiki/Supramolecular_chemistry" title="Supramolecular chemistry">Supramolecular effects</a> can influence these cycloadditions. The cycloaddition of <i>trans</i>-1,2-bis(4-pyridyl)ethene is directed by <a href="/wiki/Resorcinol" title="Resorcinol">resorcinol</a> in the <a href="/wiki/Solid-state_chemistry" title="Solid-state chemistry">solid-state</a> in 100% <a href="/wiki/Chemical_yield" class="mw-redirect" title="Chemical yield">yield</a>.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>Some cycloadditions instead of π bonds operate through strained <a href="/wiki/Cyclopropane" title="Cyclopropane">cyclopropane</a> rings, as these have significant π character. For example, an analog for the Diels-Alder reaction is the <a href="/wiki/Quadricyclane" title="Quadricyclane">quadricyclane</a>-<a href="/wiki/DMAD" class="mw-redirect" title="DMAD">DMAD</a> reaction: </p> <figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:Qcane.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Qcane.png/500px-Qcane.png" decoding="async" width="500" height="168" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Qcane.png/750px-Qcane.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Qcane.png/1000px-Qcane.png 2x" data-file-width="1119" data-file-height="377" /></a><figcaption></figcaption></figure> <p>In the (i+j+...) cycloaddition notation i and j refer to the number of atoms involved in the cycloaddition. In this notation, a Diels-Alder reaction is a (4+2)cycloaddition and a 1,3-dipolar addition such as the first step in <a href="/wiki/Ozonolysis" title="Ozonolysis">ozonolysis</a> is a (3+2)cycloaddition. The <a href="/wiki/IUPAC" class="mw-redirect" title="IUPAC">IUPAC</a> preferred notation however, with [i+j+...] takes electrons into account and not atoms. In this notation, the DA reaction and the dipolar reaction both become a [4+2]cycloaddition. The reaction between <a href="/wiki/Norbornadiene" title="Norbornadiene">norbornadiene</a> and an activated <a href="/wiki/Alkyne" title="Alkyne">alkyne</a> is a [2+2+2]cycloaddition. </p> <div class="mw-heading mw-heading2"><h2 id="Types_of_cycloaddition">Types of cycloaddition</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=3" title="Edit section: Types of cycloaddition"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Category:Cycloadditions" title="Category:Cycloadditions">Category:Cycloadditions</a></div> <div class="mw-heading mw-heading3"><h3 id="Diels-Alder_reactions">Diels-Alder reactions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=4" title="Edit section: Diels-Alder reactions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Diels-Alder_reaction" class="mw-redirect" title="Diels-Alder reaction">Diels-Alder reaction</a> is perhaps the most important and commonly taught cycloaddition reaction. Formally it is a [4+2] cycloaddition reaction and exists in a huge range of forms, including the <a href="/wiki/Inverse_electron-demand_Diels%E2%80%93Alder_reaction" title="Inverse electron-demand Diels–Alder reaction">inverse electron-demand Diels–Alder reaction</a>, <a href="/wiki/Hexadehydro_Diels%E2%80%93Alder_reaction" title="Hexadehydro Diels–Alder reaction">hexadehydro Diels–Alder reaction</a> and the related <a href="/wiki/Alkyne_trimerisation" title="Alkyne trimerisation">alkyne trimerisation</a>. The reaction can also be run in reverse in the <a href="/wiki/Retro-Diels%E2%80%93Alder_reaction" title="Retro-Diels–Alder reaction">retro-Diels–Alder reaction</a>. </p> <dl><dd><span typeof="mw:File"><a href="/wiki/File:Diels-Alder_(1,3-butadiene_%2B_ethylene)_red.svg" class="mw-file-description" title="Diels–Alder reaction"><img alt="Diels–Alder reaction" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/92/Diels-Alder_%281%2C3-butadiene_%2B_ethylene%29_red.svg/300px-Diels-Alder_%281%2C3-butadiene_%2B_ethylene%29_red.svg.png" decoding="async" width="300" height="107" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/92/Diels-Alder_%281%2C3-butadiene_%2B_ethylene%29_red.svg/450px-Diels-Alder_%281%2C3-butadiene_%2B_ethylene%29_red.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/92/Diels-Alder_%281%2C3-butadiene_%2B_ethylene%29_red.svg/600px-Diels-Alder_%281%2C3-butadiene_%2B_ethylene%29_red.svg.png 2x" data-file-width="638" data-file-height="227" /></a></span></dd></dl> <p>Reactions involving heteroatoms are known, including the <a href="/wiki/Aza-Diels%E2%80%93Alder_reaction" title="Aza-Diels–Alder reaction">aza-Diels–Alder reaction</a> and <a href="/wiki/Oxo-Diels%E2%80%93Alder_reaction" title="Oxo-Diels–Alder reaction">oxo-Diels–Alder reaction</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Huisgen_cycloadditions">Huisgen cycloadditions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=5" title="Edit section: Huisgen cycloadditions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Huisgen_cycloaddition" class="mw-redirect" title="Huisgen cycloaddition">Huisgen cycloaddition</a> reaction is a (2+3)cycloaddition. </p> <dl><dd><span typeof="mw:File"><a href="/wiki/File:Thermal_Huisgen_cycloaddition.png" class="mw-file-description" title="1,3-cycloaddition"><img alt="1,3-cycloaddition" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Thermal_Huisgen_cycloaddition.png/600px-Thermal_Huisgen_cycloaddition.png" decoding="async" width="600" height="129" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Thermal_Huisgen_cycloaddition.png/900px-Thermal_Huisgen_cycloaddition.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Thermal_Huisgen_cycloaddition.png/1200px-Thermal_Huisgen_cycloaddition.png 2x" data-file-width="5502" data-file-height="1186" /></a></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="Nitrone-olefin_cycloaddition">Nitrone-olefin cycloaddition</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=6" title="Edit section: Nitrone-olefin cycloaddition"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Nitrone-olefin_3%2B2_cycloaddition" class="mw-redirect" title="Nitrone-olefin 3+2 cycloaddition">Nitrone-olefin cycloaddition</a> is a (3+2)cycloaddition. </p> <dl><dd><span class="mw-default-size" typeof="mw:File"><a href="/wiki/File:NitrGen.svg" class="mw-file-description" title="Nitrone olefin cycloaddition"><img alt="Nitrone olefin cycloaddition" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e0/NitrGen.svg/498px-NitrGen.svg.png" decoding="async" width="498" height="96" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e0/NitrGen.svg/747px-NitrGen.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e0/NitrGen.svg/996px-NitrGen.svg.png 2x" data-file-width="498" data-file-height="96" /></a></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="Cheletropic_reactions">Cheletropic reactions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=7" title="Edit section: Cheletropic reactions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Cheletropic_reaction" title="Cheletropic reaction">Cheletropic reactions</a> are a subclass of cycloadditions. The key distinguishing feature of cheletropic reactions is that on one of the reagents, both new bonds are being made to the same atom. The classic example is the reaction of <a href="/wiki/Sulfur_dioxide" title="Sulfur dioxide">sulfur dioxide</a> with a <a href="/wiki/Diene" title="Diene">diene</a>. </p> <dl><dd><span typeof="mw:File"><a href="/wiki/File:Cheletropic_reaction_of_butadiene_with_SO2.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Cheletropic_reaction_of_butadiene_with_SO2.svg/150px-Cheletropic_reaction_of_butadiene_with_SO2.svg.png" decoding="async" width="150" height="63" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Cheletropic_reaction_of_butadiene_with_SO2.svg/225px-Cheletropic_reaction_of_butadiene_with_SO2.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Cheletropic_reaction_of_butadiene_with_SO2.svg/300px-Cheletropic_reaction_of_butadiene_with_SO2.svg.png 2x" data-file-width="380" data-file-height="160" /></a></span></dd></dl> <div class="mw-heading mw-heading2"><h2 id="Other">Other</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=8" title="Edit section: Other"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Other cycloaddition reactions exist: <a href="/wiki/(4%2B3)_cycloaddition" title="(4+3) cycloaddition">(4+3) cycloadditions</a>, <a href="/wiki/6%2B4_cycloaddition" class="mw-redirect" title="6+4 cycloaddition">[6+4] cycloadditions</a>, <a href="/wiki/Woodward-Hoffmann_rules" class="mw-redirect" title="Woodward-Hoffmann rules">[2 + 2] photocycloadditions</a>, <a href="/wiki/Metal-centered_cycloaddition_reactions" title="Metal-centered cycloaddition reactions">metal-centered cycloaddition</a> and <a href="/wiki/4%2B4_photocycloaddition" class="mw-redirect" title="4+4 photocycloaddition">[4+4] photocycloadditions</a> </p> <div class="mw-heading mw-heading2"><h2 id="Formal_cycloadditions">Formal cycloadditions</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=9" title="Edit section: Formal cycloadditions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Cycloadditions often have metal-catalyzed and stepwise <a href="/wiki/Radical_(chemistry)" title="Radical (chemistry)">radical</a> analogs, however these are not strictly speaking pericyclic reactions. When in a cycloaddition charged or radical intermediates are involved or when the cycloaddition result is obtained in a series of reaction steps they are sometimes called <b>formal cycloadditions</b> to make the distinction with true pericyclic cycloadditions. </p><p>One example of a formal [3+3]cycloaddition between a cyclic <a href="/wiki/Enone" class="mw-redirect" title="Enone">enone</a> and an <a href="/wiki/Enamine" title="Enamine">enamine</a> catalyzed by <a href="/wiki/N-Butyllithium" title="N-Butyllithium"><i>n</i>-butyllithium</a> is a <a href="/wiki/Stork_enamine_reaction" class="mw-redirect" title="Stork enamine reaction">Stork enamine</a> / <a href="/wiki/Nucleophilic_addition" title="Nucleophilic addition">1,2-addition</a> <a href="/wiki/Cascade_reaction" title="Cascade reaction">cascade reaction</a>:<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:3%2B3_cycloaddition_-_cyclic_iminium_to_cyclic_enone.svg" class="mw-file-description" title="An intermolecular formal [3+3] cycloaddition between an cyclic iminium chloride and cyclopentenone."><img alt="An intermolecular formal [3+3] cycloaddition between an cyclic iminium chloride and cyclopentenone." src="//upload.wikimedia.org/wikipedia/commons/thumb/5/53/3%2B3_cycloaddition_-_cyclic_iminium_to_cyclic_enone.svg/500px-3%2B3_cycloaddition_-_cyclic_iminium_to_cyclic_enone.svg.png" decoding="async" width="500" height="277" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/53/3%2B3_cycloaddition_-_cyclic_iminium_to_cyclic_enone.svg/750px-3%2B3_cycloaddition_-_cyclic_iminium_to_cyclic_enone.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/53/3%2B3_cycloaddition_-_cyclic_iminium_to_cyclic_enone.svg/1000px-3%2B3_cycloaddition_-_cyclic_iminium_to_cyclic_enone.svg.png 2x" data-file-width="433" data-file-height="240" /></a><figcaption>An intermolecular formal [3+3] cycloaddition between an cyclic iminium chloride and cyclopentenone.</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="Iron-catalyzed_2+2_olefin_cycloaddition"><span id="Iron-catalyzed_2.2B2_olefin_cycloaddition"></span>Iron-catalyzed 2+2 olefin cycloaddition</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=10" title="Edit section: Iron-catalyzed 2+2 olefin cycloaddition"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Iron[<a href="/wiki/Diiminopyridine" title="Diiminopyridine">pyridine(diimine)</a>] catalysts contain a redox active ligand in which the central iron atom can coordinate with two simple, unfunctionalized olefin double bonds. The catalyst can be written as a resonance between a structure containing unpaired electrons with the central iron atom in the II oxidation state, and one in which the iron is in the 0 oxidation state. This gives it the flexibility to engage in binding the double bonds as they undergo a cyclization reaction, generating a cyclobutane structure via C-C reductive elimination; alternatively a cyclobutene structure may be produced by beta-hydrogen elimination. Efficiency of the reaction varies substantially depending on the alkenes used, but rational ligand design may permit expansion of the range of reactions that can be catalyzed.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cycloaddition&action=edit&section=11" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width reflist-columns-2"> <ol class="references"> <li id="cite_note-goldbook-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-goldbook_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-goldbook_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-goldbook_1-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://goldbook.iupac.org/html/C/C01496.html">"cycloaddition"</a>, <i>IUPAC Compendium of Chemical Terminology</i>, IUPAC, 2009, <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1351%2Fgoldbook.C01496">10.1351/goldbook.C01496</a></span>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-9678550-9-7" title="Special:BookSources/978-0-9678550-9-7"><bdi>978-0-9678550-9-7</bdi></a><span class="reference-accessdate">, retrieved <span class="nowrap">2018-10-13</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IUPAC+Compendium+of+Chemical+Terminology&rft.atitle=cycloaddition&rft.date=2009&rft_id=info%3Adoi%2F10.1351%2Fgoldbook.C01496&rft.isbn=978-0-9678550-9-7&rft_id=https%3A%2F%2Fgoldbook.iupac.org%2Fhtml%2FC%2FC01496.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://goldbook.iupac.org/html/P/P04491.html">"pericyclic reaction"</a>, <i>IUPAC Compendium of Chemical Terminology</i>, IUPAC, 2009, <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1351%2Fgoldbook.P04491">10.1351/goldbook.P04491</a></span>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-9678550-9-7" title="Special:BookSources/978-0-9678550-9-7"><bdi>978-0-9678550-9-7</bdi></a><span class="reference-accessdate">, retrieved <span class="nowrap">2018-10-13</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IUPAC+Compendium+of+Chemical+Terminology&rft.atitle=pericyclic+reaction&rft.date=2009&rft_id=info%3Adoi%2F10.1351%2Fgoldbook.P04491&rft.isbn=978-0-9678550-9-7&rft_id=https%3A%2F%2Fgoldbook.iupac.org%2Fhtml%2FP%2FP04491.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIzzottiGleason2022" class="citation cs2">Izzotti, Anthony; Gleason, James (2022-06-07), <a rel="nofollow" class="external text" href="https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/chem.202201418">"Do Antarafacial Cycloadditions Occur? Cycloaddition of Heptafulvalene with Tetracyanoethylene"</a>, <i>Chemistry: A European Journal</i>, <b>28</b> (49), <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fchem.202201418">10.1002/chem.202201418</a>, <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/35671245">35671245</a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chemistry%3A+A+European+Journal&rft.atitle=Do+Antarafacial+Cycloadditions+Occur%3F+Cycloaddition+of+Heptafulvalene+with+Tetracyanoethylene&rft.volume=28&rft.issue=49&rft.date=2022-06-07&rft_id=info%3Adoi%2F10.1002%2Fchem.202201418&rft_id=info%3Apmid%2F35671245&rft.aulast=Izzotti&rft.aufirst=Anthony&rft.au=Gleason%2C+James&rft_id=https%3A%2F%2Fchemistry-europe.onlinelibrary.wiley.com%2Fdoi%2Fepdf%2F10.1002%2Fchem.202201418&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFErdenKauFmann1981" class="citation journal cs1 cs1-prop-foreign-lang-source">Erden, Ihsan; KauFmann, Dieter (1981-01-01). <a rel="nofollow" class="external text" href="https://dx.doi.org/10.1016/0040-4039%2881%2980058-5">"Cycloadditionsreaktionen des heptafulvalens"</a>. <i>Tetrahedron Letters</i> (in German). <b>22</b> (3): <span class="nowrap">215–</span>218. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0040-4039%2881%2980058-5">10.1016/0040-4039(81)80058-5</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0040-4039">0040-4039</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Tetrahedron+Letters&rft.atitle=Cycloadditionsreaktionen+des+heptafulvalens&rft.volume=22&rft.issue=3&rft.pages=%3Cspan+class%3D%22nowrap%22%3E215-%3C%2Fspan%3E218&rft.date=1981-01-01&rft_id=info%3Adoi%2F10.1016%2F0040-4039%2881%2980058-5&rft.issn=0040-4039&rft.aulast=Erden&rft.aufirst=Ihsan&rft.au=KauFmann%2C+Dieter&rft_id=https%3A%2F%2Fdx.doi.org%2F10.1016%2F0040-4039%252881%252980058-5&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHein,_Sara_M.2006" class="citation journal cs1">Hein, Sara M. (June 2006). "An Exploration of a Photochemical Pericyclic Reaction Using NMR Data". <i>Journal of Chemical Education</i>. <b>83</b> (6): <span class="nowrap">940–</span>942. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006JChEd..83..940H">2006JChEd..83..940H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fed083p940">10.1021/ed083p940</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Education&rft.atitle=An+Exploration+of+a+Photochemical+Pericyclic+Reaction+Using+NMR+Data&rft.volume=83&rft.issue=6&rft.pages=%3Cspan+class%3D%22nowrap%22%3E940-%3C%2Fspan%3E942&rft.date=2006-06&rft_id=info%3Adoi%2F10.1021%2Fed083p940&rft_id=info%3Abibcode%2F2006JChEd..83..940H&rft.au=Hein%2C+Sara+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFL._R._MacGillivrayJ._L._ReidJ._A._Ripmeester2000" class="citation journal cs1">L. R. MacGillivray; J. L. Reid; J. A. Ripmeester (2000). "Supramolecular Control of Reactivity in the Solid State Using Linear Molecular Templates". <i><a href="/wiki/J._Am._Chem._Soc." class="mw-redirect" title="J. Am. Chem. Soc.">J. Am. Chem. Soc.</a></i> <b>122</b> (32): <span class="nowrap">7817–</span>7818. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fja001239i">10.1021/ja001239i</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=J.+Am.+Chem.+Soc.&rft.atitle=Supramolecular+Control+of+Reactivity+in+the+Solid+State+Using+Linear+Molecular+Templates&rft.volume=122&rft.issue=32&rft.pages=%3Cspan+class%3D%22nowrap%22%3E7817-%3C%2Fspan%3E7818&rft.date=2000&rft_id=info%3Adoi%2F10.1021%2Fja001239i&rft.au=L.+R.+MacGillivray&rft.au=J.+L.+Reid&rft.au=J.+A.+Ripmeester&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMovassaghiBin_Chen2007" class="citation journal cs1">Movassaghi, Mohammad; Bin Chen (2007). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510678">"Stereoselective Intermolecular Formal [3+3] Cycloaddition Reaction of Cyclic Enamines and Enones"</a>. <i><a href="/wiki/Angew._Chem._Int._Ed." class="mw-redirect" title="Angew. Chem. Int. Ed.">Angew. Chem. Int. Ed.</a></i> <b>46</b> (4): <span class="nowrap">565–</span>568. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fanie.200603302">10.1002/anie.200603302</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510678">3510678</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17146819">17146819</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Angew.+Chem.+Int.+Ed.&rft.atitle=Stereoselective+Intermolecular+Formal+%5B3%2B3%5D+Cycloaddition+Reaction+of+Cyclic+Enamines+and+Enones&rft.volume=46&rft.issue=4&rft.pages=%3Cspan+class%3D%22nowrap%22%3E565-%3C%2Fspan%3E568&rft.date=2007&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3510678%23id-name%3DPMC&rft_id=info%3Apmid%2F17146819&rft_id=info%3Adoi%2F10.1002%2Fanie.200603302&rft.aulast=Movassaghi&rft.aufirst=Mohammad&rft.au=Bin+Chen&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3510678&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJordan_M._HoytValeria_A._SchmidtAaron_M._TondreauPaul_J._Chirik2015" class="citation journal cs1">Jordan M. Hoyt; Valeria A. Schmidt; Aaron M. Tondreau; <a href="/wiki/Paul_Chirik" title="Paul Chirik">Paul J. Chirik</a> (2015-08-28). "Iron-catalyzed intermolecular [2+2] cycloadditions of unactivated alkenes". <i>Science</i>. <b>349</b> (6251): <span class="nowrap">960–</span>963. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2015Sci...349..960H">2015Sci...349..960H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.aac7440">10.1126/science.aac7440</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/26315433">26315433</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:206640239">206640239</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Iron-catalyzed+intermolecular+%5B2%2B2%5D+cycloadditions+of+unactivated+alkenes&rft.volume=349&rft.issue=6251&rft.pages=%3Cspan+class%3D%22nowrap%22%3E960-%3C%2Fspan%3E963&rft.date=2015-08-28&rft_id=info%3Adoi%2F10.1126%2Fscience.aac7440&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A206640239%23id-name%3DS2CID&rft_id=info%3Apmid%2F26315433&rft_id=info%3Abibcode%2F2015Sci...349..960H&rft.au=Jordan+M.+Hoyt&rft.au=Valeria+A.+Schmidt&rft.au=Aaron+M.+Tondreau&rft.au=Paul+J.+Chirik&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACycloaddition" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMyles_W._SmithPhil_S._Baran2015" class="citation journal cs1">Myles W. Smith; <a href="/wiki/Phil_S._Baran" title="Phil S. Baran">Phil S. Baran</a> (2015-08-28). "As simple as [2+2]". <i>Science</i>. <b>349</b> (6251): <span class="nowrap">925–</span>926. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2015Sci...349..925S">2015Sci...349..925S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.aac9883">10.1126/science.aac9883</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/26315420">26315420</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:42226757">42226757</a>.</cite><span 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href="/wiki/SN1_reaction" title="SN1 reaction">Unimolecular nucleophilic substitution</a> (S<sub>N</sub>1)</li> <li><a href="/wiki/SN2_reaction" title="SN2 reaction">Bimolecular nucleophilic substitution</a> (S<sub>N</sub>2)</li> <li><a href="/wiki/Nucleophilic_aromatic_substitution" title="Nucleophilic aromatic substitution">Nucleophilic aromatic substitution</a> (S<sub>N</sub>Ar)</li> <li><a href="/wiki/SNi" title="SNi">Nucleophilic internal substitution</a> (S<sub>N</sub>i)</li> <li><a href="/wiki/Nucleophilic_acyl_substitution" class="mw-redirect" title="Nucleophilic acyl substitution">Nucleophilic acyl substitution</a> (S<sub>N</sub>Acyl)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Electrophilic_substitution" title="Electrophilic substitution">Electrophilic substitutions</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Electrophilic_aromatic_substitution" title="Electrophilic aromatic substitution">Electrophilic aromatic substitution</a> (S<sub>E</sub>Ar)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Elimination_reaction" title="Elimination reaction">Elimination reactions</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/E1_elimination" class="mw-redirect" title="E1 elimination">Unimolecular elimination</a> (E1)</li> <li><a href="/wiki/E1cB-elimination_reaction" title="E1cB-elimination reaction">E1cB-elimination</a></li> <li><a href="/wiki/E2_elimination" class="mw-redirect" title="E2 elimination">Bimolecular elimination</a> (E2)</li> <li><a href="/wiki/Ei_mechanism" title="Ei mechanism">E<sub>i</sub> elimination</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Addition_reaction" title="Addition reaction">Addition reactions</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Electrophilic_addition" title="Electrophilic addition">Electrophilic addition</a> (A<sub>E</sub>)</li> <li><a href="/wiki/Nucleophilic_addition" title="Nucleophilic addition">Nucleophilic addition</a> (A<sub>N</sub>)</li> <li><a href="/wiki/Free-radical_addition" title="Free-radical addition">Free-radical addition</a></li> <li><a class="mw-selflink selflink">Cycloaddition</a></li> <li><a href="/wiki/Oxidative_addition" title="Oxidative addition">Oxidative addition</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Unimolecular reactions</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Intramolecular_reaction" title="Intramolecular reaction">Intramolecular reaction</a></li> <li><a href="/wiki/Isomerization" title="Isomerization">Isomerization</a></li> <li><a href="/wiki/Photodissociation" title="Photodissociation">Photodissociation</a></li> <li><a href="/wiki/Lindemann%E2%80%93Hinshelwood_mechanism" class="mw-redirect" title="Lindemann–Hinshelwood mechanism">Lindemann–Hinshelwood mechanism</a></li> <li><a href="/wiki/RRKM_theory" title="RRKM theory">RRKM theory</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Electron_transfer" title="Electron transfer">Electron/Proton transfer</a> reactions</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Redox" title="Redox">Redox</a></li> <li><a href="/wiki/Harpoon_reaction" title="Harpoon reaction">Harpoon reaction</a></li> <li><a href="/wiki/Grotthuss_mechanism" title="Grotthuss mechanism">Grotthuss mechanism</a></li> <li><a href="/wiki/Marcus_theory" title="Marcus theory">Marcus theory</a></li> <li><a href="/wiki/Inner_sphere_electron_transfer" title="Inner sphere electron transfer">Inner sphere electron transfer</a></li> <li><a href="/wiki/Outer_sphere_electron_transfer" title="Outer sphere electron transfer">Outer sphere electron transfer</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Medium effects</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Solvent_effects" title="Solvent effects">Solvent effects</a></li> <li><a href="/wiki/Cage_effect" title="Cage effect">Cage effect</a></li> <li><a href="/wiki/Matrix_isolation" title="Matrix isolation">Matrix isolation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related topics</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Elementary_reaction" title="Elementary reaction">Elementary reaction</a></li> <li><a href="/wiki/Reaction_dynamics" title="Reaction dynamics">Reaction dynamics</a></li> <li><a href="/wiki/Reactive_intermediate" title="Reactive intermediate">Reactive intermediate</a></li> <li><a href="/wiki/Radical_(chemistry)" title="Radical (chemistry)">Radical (chemistry)</a></li> <li><a href="/wiki/Molecularity" title="Molecularity">Molecularity</a></li> <li><a href="/wiki/Stereochemistry" title="Stereochemistry">Stereochemistry</a></li> <li><a href="/wiki/Catalysis" title="Catalysis">Catalysis</a></li> <li><a href="/wiki/Collision_theory" title="Collision theory">Collision theory</a></li> <li><a href="/wiki/Arrow_pushing" title="Arrow pushing">Arrow pushing</a></li> <li><a href="/wiki/Potential_energy_surface" title="Potential energy surface">Potential energy surface</a></li> <li><a href="/wiki/More_O%27Ferrall%E2%80%93Jencks_plot" title="More O'Ferrall–Jencks plot">More O'Ferrall–Jencks plot</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Chemical_kinetics" title="Chemical kinetics">Chemical kinetics</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Rate_equation" title="Rate equation">Rate equation</a></li> <li><a href="/wiki/Equilibrium_constant" title="Equilibrium constant">Equilibrium constant</a></li> <li><a href="/wiki/Rate-determining_step" title="Rate-determining step">Rate-determining step</a></li> <li><a href="/wiki/Reaction_coordinate" title="Reaction coordinate">Reaction coordinate</a></li> <li><a href="/wiki/Energy_profile_(chemistry)" title="Energy profile (chemistry)">Energy profile (chemistry)</a></li> <li><a href="/wiki/Transition_state_theory" title="Transition state theory">Transition state theory</a></li> <li><a href="/wiki/Activation_energy" title="Activation energy">Activation energy</a></li> <li><a href="/wiki/Activated_complex" title="Activated complex">Activated complex</a></li> <li><a href="/wiki/Arrhenius_equation" title="Arrhenius equation">Arrhenius equation</a></li> <li><a href="/wiki/Eyring_equation" title="Eyring equation">Eyring equation</a></li> <li><a href="/wiki/Michaelis%E2%80%93Menten_kinetics" title="Michaelis–Menten kinetics">Michaelis–Menten kinetics</a></li> <li><a href="/wiki/Diffusion-controlled_reaction" title="Diffusion-controlled reaction">Diffusion-controlled reaction</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r1038841319">.mw-parser-output .tooltip-dotted{border-bottom:1px 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