{"id":7434,"date":"2012-08-06T14:01:21","date_gmt":"2012-08-06T13:01:21","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=7434"},"modified":"2012-08-06T14:01:21","modified_gmt":"2012-08-06T13:01:21","slug":"the-curtius-rearrangement-one-step-or-two","status":"publish","type":"post","link":"https:\/\/rzepa.net\/blog\/2012\/08\/06\/the-curtius-rearrangement-one-step-or-two\/","title":{"rendered":"The Curtius rearrangement. One step or two?"},"content":{"rendered":"<p>The Curtius reaction is represented in most chemistry texts and notes as following path (a) below. It is one of a general class of thermally induced rearrangement which might be described as elimination\/migration (in a sense similar to this <a href=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=6279\" target=\"_blank\">ring contraction migration\/elimination<\/a>), in this case implicating a nitrene intermediate if the two steps occur consecutively. Wikipedia is normally very much on the ball with this sort of thing, and a <a href=\"http:\/\/en.wikipedia.org\/wiki\/Curtius_rearrangement\" target=\"_blank\">comment about the reaction mechanism<\/a> there notes that current evidence prefers route (b), avoiding nitrene intermediacy (and hence formally removing this from examples of nitrene reactions).<\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-7435\" title=\"curtius\" alt=\"\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/08\/curtius.svg\" \/><\/p>\n<p>So time for a reality check (which in this case takes the form of a \u03c9B97XD\/6-311G(d,p)\/SCRF=dichloromethane calculation).\u00a0<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-7436\" title=\"curtius_Small\" alt=\"\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/08\/curtius_Small.gif\" width=\"431\" height=\"273\" \/><\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-7437\" title=\"curtius_Small\" alt=\"\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/08\/curtius_Small.svg\" \/><\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-7439\" title=\"curtius_Smallg\" alt=\"\" src=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/08\/curtius_Smallg1.svg\" \/><\/p>\n<p>This is pretty clear-cut; no nitrene intermediate. Now for the standard text-books to catch up!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Curtius reaction is represented in most chemistry texts and notes as following path (a) below. It is one of a general class of thermally induced rearrangement which might be described as elimination\/migration (in a sense similar to this ring contraction migration\/elimination), in this case implicating a nitrene intermediate if the two steps occur consecutively. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[891,1643,1884,2076,2489],"class_list":["post-7434","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-elimination","tag-migration","tag-pericyclic","tag-reaction-mechanism","tag-tutorial-material"],"_links":{"self":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/posts\/7434","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/comments?post=7434"}],"version-history":[{"count":0,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/posts\/7434\/revisions"}],"wp:attachment":[{"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/media?parent=7434"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/categories?post=7434"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rzepa.net\/blog\/wp-json\/wp\/v2\/tags?post=7434"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}