{"id":5950,"date":"2011-12-15T17:36:19","date_gmt":"2011-12-15T17:36:19","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=5950"},"modified":"2013-05-07T17:29:43","modified_gmt":"2013-05-07T16:29:43","slug":"molecular-gymnastics-in-22-cycloadditions-two-different-moves-compared","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=5950","title":{"rendered":"Molecular gymnastics in  2+2 cycloadditions. Two different moves compared."},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"5950\">\n<p>The <a href=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=5927\" target=\"_blank\">previous post<\/a> showed how the 2+2 cycloaddition of an alkene could occur by a sort of sideways insinuation of the bonds. I have also shown how the same reaction can occur with a dramatic rotation of one of the double bonds. This post compares the two moves side by side.<\/p>\n<p style=\"text-align: center;\"><a href=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/12\/a+s.svg\"><img decoding=\"async\" class=\"aligncenter  wp-image-5952\" title=\"a+s\" alt=\"\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/12\/a+s.svg\" width=\"300\" \/><\/a><\/p>\n<table style=\"margin-left: auto; margin-right: auto;\" border=\"1\">\n<tbody>\n<tr>\n<td align=\"centre\"><a href=\"http:\/\/hdl.handle.net\/10042\/to-11413\" target=\"_blank\">0.0<\/a><\/td>\n<td align=\"centre\"><a href=\"http:\/\/hdl.handle.net\/10042\/to-11415\" target=\"_blank\">5.3 kcal\/mol<\/a><\/td>\n<\/tr>\n<tr>\n<td>\n<div id=\"attachment_5933\" style=\"width: 232px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/hdl.handle.net\/10042\/to-11331\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-5933\" class=\" wp-image-5933  \" title=\"14d1\" alt=\"\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/12\/14d1.gif\" width=\"222\" height=\"136\" \/><\/a><p id=\"caption-attachment-5933\" class=\"wp-caption-text\">The forbidden dance<\/p><\/div>\n<\/td>\n<td>\n<div id=\"attachment_5958\" style=\"width: 213px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/hdl.handle.net\/10042\/to-11399\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-5958\" class=\" wp-image-5958 \" title=\"2a+2s-CS\" alt=\"\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/12\/2a+2s-CS1.gif\" width=\"203\" height=\"143\" \/><\/a><p id=\"caption-attachment-5958\" class=\"wp-caption-text\">The allowed dance.<\/p><\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>As is sometimes the case in real life, the forbidden option has the lower activation barrier!<\/p>\n<!-- kcite active, but no citations found -->\n<\/div> <!-- kcite-section 5950 -->","protected":false},"excerpt":{"rendered":"<p>The previous post showed how the 2+2 cycloaddition of an alkene could occur by a sort of sideways insinuation of the bonds. I have also shown how the same reaction can occur with a dramatic rotation of one of the double bonds. This post compares the two moves side by side. 0.0 5.3 kcal\/mol As [&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":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[4],"tags":[2650,373],"ppma_author":[2661],"class_list":["post-5950","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-pericyclic","tag-tutorial-material"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Molecular gymnastics in 2+2 cycloadditions. Two different moves compared. - 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=5950\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Molecular gymnastics in 2+2 cycloadditions. Two different moves compared. - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"The previous post showed how the 2+2 cycloaddition of an alkene could occur by a sort of sideways insinuation of the bonds. I have also shown how the same reaction can occur with a dramatic rotation of one of the double bonds. This post compares the two moves side by side. 0.0 5.3 kcal\/mol As [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=5950\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2011-12-15T17:36:19+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2013-05-07T16:29:43+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/12\/a+s.svg\" \/>\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<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Molecular gymnastics in 2+2 cycloadditions. Two different moves compared. - 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=5950","og_locale":"en_GB","og_type":"article","og_title":"Molecular gymnastics in 2+2 cycloadditions. Two different moves compared. - Henry Rzepa&#039;s Blog","og_description":"The previous post showed how the 2+2 cycloaddition of an alkene could occur by a sort of sideways insinuation of the bonds. I have also shown how the same reaction can occur with a dramatic rotation of one of the double bonds. 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