{"id":26812,"date":"2024-02-19T17:05:05","date_gmt":"2024-02-19T17:05:05","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=26812"},"modified":"2025-08-21T14:06:12","modified_gmt":"2025-08-21T13:06:12","slug":"mechanistic-templates-computed-for-the-grubbs-alkene-metathesis-reaction","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812","title":{"rendered":"Mechanistic templates computed for the Grubbs alkene-metathesis reaction."},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"26812\">\n<p>Following on from my template exploration of the Wilkinson hydrogenation catalyst, I now repeat this for the Grubbs variant of the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Olefin_metathesis\">Alkene metathesis<\/a> reaction. As with the Wilkinson, here I focus on the stereochemistry of the mechanism as first suggested by Chauvin<span id=\"cite_ITEM-26812-0\" name=\"citation\"><a href=\"#ITEM-26812-0\">[1]<\/a><\/span>, an aspect lacking in eg the Wikipedia entry. As before, the diagram below is hyperlinked to the appropriate data repository identifier so that you can go straight from the scheme to the data (Top level Data DOI: <span id=\"cite_ITEM-26812-1\" name=\"citation\"><a href=\"#ITEM-26812-1\">[2]<\/a><\/span>).<\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/grubbs.svg\"><img decoding=\"async\" class=\"aligncenter size-full wp-image-26863\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/grubbs.svg\" alt=\"\" width=\"540\" \/><\/a><\/p>\n<p>The essence of the reaction is the formation of a metallacyclobutane intermediate, which being approximately symmetrical with a plane of symmetry, can revert to the catalyst and an alkene in one of two ways, reforming the original alkene (two red dot carbons) or a forming a methathesised alkene (red-blue dot carbons).<\/p>\n<p>Although the mechanism is often described as a [2+2] cycloaddition in which d-orbital participation from the metal lowers the activation energy significantly, calculations at the MN15L\/Def2-TZVPPD\/SCRF level\u00a0indicate there can be up to four discrete steps involved in the process. There are three routes involving these steps that the calculations (B3LYP+GD3+BJ\/Def2-TZVPPD\/SCRF=DCM) reveal (DataDOI <span id=\"cite_ITEM-26812-1\" name=\"citation\"><a href=\"#ITEM-26812-1\">[2]<\/a><\/span>). The starting point for all three routes is the most stable reactant catalyst (left above) which has the H-C-H carbene group in the same plane as the P-Ru-P atoms.<\/p>\n<ol>\n<li>The <strong>red route<\/strong> involves the following steps:\n<ul>\n<li>Activation of the catalyst by rotation of the carbene from its lowest energy orientation by 90\u00b0.<\/li>\n<li>followed by addition of an alkene to form a \u03c0-complex &#8211;<\/li>\n<li>then formation of a C-C bond between the alkene and the carbene (animation below). The remarkable feature of this third step is that the carbene group must again rotate through 90\u00b0 (indicated with a red rotational arrow in scheme above) prior to finally forming the C-C bond.<br \/>\n<img decoding=\"async\" class=\"aligncenter size-full wp-image-26848\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/13834.gif\" alt=\"\" width=\"440\"  \/><\/li>\n<\/ul>\n<\/li>\n<li>The <strong>magenta route<\/strong> involves only one step, in which addition of the alkene is directly followed in a second stage by C-C bond formation, <em>via<\/em> what is called the &#8220;hidden intermediate&#8221; of the alkene complex (visible at ~IRC -3 for the energy profile below)<br \/>\n<a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/Grubbs-_tot_ener.svg\"><img decoding=\"async\" class=\"aligncenter size-full wp-image-26844\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/Grubbs-_tot_ener.svg\" alt=\"\" width=\"440\" \/><img decoding=\"async\" class=\"aligncenter size-full wp-image-26845\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/Grubbs-_tot_ener.gif\" alt=\"\" width=\"440\" \/><\/a><\/li>\n<li>The <strong>green<\/strong> and final route again involves up to four steps:\n<ul>\n<li>A pseudorotation to place the two chlorine atoms di-axial,<a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/13827.svg\"><img decoding=\"async\" class=\"aligncenter size-full wp-image-26858\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/13827.svg\" alt=\"\" width=\"440\" \/><\/a><br \/>\n<img decoding=\"async\" class=\"aligncenter size-full wp-image-26852\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/pseudorot.gif\" alt=\"\" width=\"440\" \/><\/li>\n<li>next, addition of an alkene to form a \u03c0-complex<\/li>\n<li>immediately followed C-C formation between alkene and carbene, again with twisting of the carbene group in the final step. The combined IRC for the last two of these steps (below) shows that the alkene \u03c0-complex in fact sits in shallow but real minimum, compared to it being only a &#8220;hidden intermediate&#8221; in the magenta route.<br \/><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/RuF_tot_ener-3.svg\">\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-26853\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/RuF_tot_ener-3.svg\" alt=\"\" width=\"440\" \/><\/p>\n<p><\/a><\/li>\n<li>The reaction can either reverse as this stage to eliminate a different alkene, \u00a0or progress through one final pseudorotation step to rejoin the product of the red and magenta routes.<br \/>\n<img decoding=\"async\" onclick=\"jmolApplet([450,450],'load wp-content\/uploads\/2024\/02\/Grubbs-route3.log;frame 49;set antialiasDisplay ON;vectors on;measure 15 16;vectors 4;vectors scale 8.0;color vectors green;vibration 6;','c1');\" class=\"aligncenter size-full wp-image-26849\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/13803.gif\" alt=\"\" width=\"440\" \/><br \/>\nClick on image above to get 3D model of the transition state.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p>Of the three routes, the green one has the lowest &#8220;high energy&#8221; point, corresponding to a barrier of \u0394G<sup>\u2021<\/sup> 14.7 kcal\/mol, which corresponds to the facile room temperature reaction it is. The two almost-equal high points are the initial pseudorotation and the alkene complexation, although the final C-C bond formation is also very similar in energy.<\/p>\n<p>So we have learnt that this mechanism is actually a bit more complex than is normally shown and that two of the steps (red and green) involve a very unusual methylene rotation accompanying the C-C bond formation. No doubt, the stereoelectronic orbital interactions responsible for this are fascinating, but an analysis of these will have to wait for another post.<\/p>\n<h2>References<\/h2>\n    <ol class=\"kcite-bibliography csl-bib-body\"><li id=\"ITEM-26812-0\">P. Jean\u2010Louis H\u00e9risson, and Y. Chauvin, \"Catalyse de transformation des ol\u00e9fines par les complexes du tungst\u00e8ne. II. T\u00e9lom\u00e9risation des ol\u00e9fines cycliques en pr\u00e9sence d&#039;ol\u00e9fines acycliques\", <i>Die Makromolekulare Chemie<\/i>, vol. 141, pp. 161-176, 1971. <a href=\"https:\/\/doi.org\/10.1002\/macp.1971.021410112\">https:\/\/doi.org\/10.1002\/macp.1971.021410112<\/a>\n\n<\/li>\n<li id=\"ITEM-26812-1\">H. Rzepa, \"Mechanistic templates computed for the Grubbs alkene-metathesis reaction.\", 2024. <a href=\"https:\/\/doi.org\/10.14469\/hpc\/13796\">https:\/\/doi.org\/10.14469\/hpc\/13796<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> <!-- kcite-section 26812 -->","protected":false},"excerpt":{"rendered":"<p>Following on from my template exploration of the Wilkinson hydrogenation catalyst, I now repeat this for the Grubbs variant of the Alkene metathesis reaction. As with the Wilkinson, here I focus on the stereochemistry of the mechanism as first suggested by Chauvin, an aspect lacking in eg the Wikipedia entry. As before, the diagram below [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":5,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[4],"tags":[],"ppma_author":[2661],"class_list":["post-26812","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Mechanistic templates computed for the Grubbs alkene-metathesis reaction. - Henry Rzepa&#039;s Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Mechanistic templates computed for the Grubbs alkene-metathesis reaction. - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"Following on from my template exploration of the Wilkinson hydrogenation catalyst, I now repeat this for the Grubbs variant of the Alkene metathesis reaction. As with the Wilkinson, here I focus on the stereochemistry of the mechanism as first suggested by Chauvin, an aspect lacking in eg the Wikipedia entry. As before, the diagram below [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2024-02-19T17:05:05+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-08-21T13:06:12+00:00\" \/>\n<meta name=\"author\" content=\"Henry Rzepa\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Henry Rzepa\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"5 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Mechanistic templates computed for the Grubbs alkene-metathesis reaction. - Henry Rzepa&#039;s Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812","og_locale":"en_GB","og_type":"article","og_title":"Mechanistic templates computed for the Grubbs alkene-metathesis reaction. - Henry Rzepa&#039;s Blog","og_description":"Following on from my template exploration of the Wilkinson hydrogenation catalyst, I now repeat this for the Grubbs variant of the Alkene metathesis reaction. As with the Wilkinson, here I focus on the stereochemistry of the mechanism as first suggested by Chauvin, an aspect lacking in eg the Wikipedia entry. As before, the diagram below [&hellip;]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812","og_site_name":"Henry Rzepa&#039;s Blog","article_published_time":"2024-02-19T17:05:05+00:00","article_modified_time":"2025-08-21T13:06:12+00:00","author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"5 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"Mechanistic templates computed for the Grubbs alkene-metathesis reaction.","datePublished":"2024-02-19T17:05:05+00:00","dateModified":"2025-08-21T13:06:12+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812"},"wordCount":604,"commentCount":0,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#primaryimage"},"thumbnailUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/grubbs.svg","articleSection":["Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812","name":"Mechanistic templates computed for the Grubbs alkene-metathesis reaction. - Henry Rzepa&#039;s Blog","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#primaryimage"},"thumbnailUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/grubbs.svg","datePublished":"2024-02-19T17:05:05+00:00","dateModified":"2025-08-21T13:06:12+00:00","author":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"breadcrumb":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#primaryimage","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/grubbs.svg","contentUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2024\/02\/grubbs.svg"},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26812#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"Mechanistic templates computed for the Grubbs alkene-metathesis reaction."}]},{"@type":"WebSite","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/","name":"Henry Rzepa&#039;s Blog","description":"Chemistry with a twist","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-GB"},{"@type":"Person","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281","name":"Henry Rzepa","image":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g370be3a7397865e4fd161aefeb0a5a85","url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","caption":"Henry Rzepa"},"description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London.","sameAs":["https:\/\/orcid.org\/0000-0002-8635-8390"],"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?author=1"}]}},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pDef7-6Ys","jetpack-related-posts":[{"id":7844,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7844","url_meta":{"origin":26812,"position":0},"title":"Alkene metathesis springs a surprise.","author":"Henry Rzepa","date":"October 1, 2012","format":false,"excerpt":"Alkene metathesis is part of a new generation of synthetic reaction in which a double C=C bond is formed from appropriate reactants where no bond initially exists (another example is the Wittig reaction), with the involvement\u2020 of a 4-membered-ring metallacyclobutane ring 1 (again, very similar to the Wittig). I thought\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/grubbs.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":7885,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7885","url_meta":{"origin":26812,"position":1},"title":"Alkyne metathesis: a comparison with alkene metathesis.","author":"Henry Rzepa","date":"October 8, 2012","format":false,"excerpt":"Metathesis reactions are a series of catalysed transformations which transpose the atoms in alkenes or alkynes. Alkyne metathesis is closely related to the same reaction for alkenes, and one catalyst that is specific to alkynes was introduced by Schrock (who with Grubbs won the Nobel prize for these discoveries) and\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/10\/schrock.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":12308,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=12308","url_meta":{"origin":26812,"position":2},"title":"Enantioselective epoxidation of alkenes using the  Shi Fructose-based catalyst. An undergraduate experiment.","author":"Henry Rzepa","date":"April 15, 2014","format":false,"excerpt":"The journal of chemical education can be a fertile source of ideas for undergraduate student experiments. Take this procedure for asymmetric epoxidation of an alkene. When I first spotted it, I thought not only would it be interesting to do in the lab, but could be extended by incorporating some\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":26709,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26709","url_meta":{"origin":26812,"position":3},"title":"A mechanistic exploration of the Wilkinson hydrogenation catalyst. Part 1: Model templates","author":"Henry Rzepa","date":"January 21, 2024","format":false,"excerpt":"Geoffrey Wilkinson first reported his famous work on the hydrogenation catalyst that now bears his name in 1965 and I met him at Imperial College around 1969 and again when I returned there in 1977. He was still working on these catalysts then and I was privileged to collaborate with\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":13300,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13300","url_meta":{"origin":26812,"position":4},"title":"Mechanism of the solvatochromic reaction of a spiropyran.","author":"Henry Rzepa","date":"February 4, 2015","format":false,"excerpt":"The journal of chemical education has many little gems providing inspiration for laboratory experiments. Jonathan Piard reports one based on the reaction below; here I investigate the mechanism of this transformation. There are two things going on here; an electrocyclic ring opening involving breaking the C-O bond, with\u00a0a cis\/trans isomerism\u2026","rel":"","context":"In &quot;reaction mechanism&quot;","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"cis-trans","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2015\/02\/cis-trans.gif?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":14601,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=14601","url_meta":{"origin":26812,"position":5},"title":"Yes, no, yes. Computational mechanistic exploration of (nickel-catalysed) cyclopropanation using tetramethylammonium triflate.","author":"Henry Rzepa","date":"October 1, 2015","format":false,"excerpt":"A fascinating re-examination has appeared of a reaction first published in 1960 by Wittig and then repudiated by him in 1964 since it could not be replicated by a later student. According to the new work, the secret to a successful replication\u00a0seems to be\u00a0the presence of traces of a nickel\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_likes_enabled":false,"authors":[{"term_id":2661,"user_id":1,"is_guest":0,"slug":"admin","display_name":"Henry Rzepa","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/26812","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=26812"}],"version-history":[{"count":50,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/26812\/revisions"}],"predecessor-version":[{"id":29605,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/26812\/revisions\/29605"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=26812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=26812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=26812"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=26812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}