{"id":233280,"date":"2025-06-12T21:49:11","date_gmt":"2025-06-12T21:49:11","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=233280"},"modified":"2025-06-12T21:49:13","modified_gmt":"2025-06-12T21:49:13","slug":"this-is-a-retrosynthesis-arrow","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/12\/this-is-a-retrosynthesis-arrow\/","title":{"rendered":"This is a retrosynthesis arrow"},"content":{"rendered":"\n

This is a retrosynthesis arrow. Provide cofrrect starting materials to make this product. == Ph Ph A. Ph (2 equiv.) B. Ph (2 equiv.) C. Ph (2 eqiv.) D. Ph (1 equiv<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

\u2705 Correct Answer: A. PhCOCH\u2083 (2 equiv.)<\/strong><\/h3>\n\n\n\n
\n\n\n\n

Textbook-Style Explanation <\/strong><\/h3>\n\n\n\n

The product shown is 1,3-diphenyl-1,3-propanedione<\/strong>, a \u03b2-diketone where two phenyl groups (Ph)<\/strong> are attached to each of the terminal carbonyl-containing carbons. The central carbon is methylene (CH\u2082), flanked by two carbonyls \u2014 a classic \u03b2-diketone motif<\/strong>. This type of compound is typically synthesized via a Claisen condensation<\/strong>, which is a base-catalyzed carbon\u2013carbon bond-forming reaction between two esters or one ester and one ketone.<\/p>\n\n\n\n

In this case, the reaction involves two equivalents of acetophenone (PhCOCH\u2083)<\/strong>. Under basic conditions (commonly sodium ethoxide or sodium hydride in ethanol), one molecule of acetophenone is deprotonated at the \u03b1-carbon (next to the carbonyl group) to form an enolate ion. This enolate then performs a nucleophilic attack on the carbonyl carbon of a second acetophenone molecule, forming a \u03b2-keto intermediate.<\/p>\n\n\n\n

After nucleophilic addition and proton transfer, the intermediate undergoes elimination of a leaving group (usually under heat), resulting in the \u03b2-diketone product, 1,3-diphenyl-1,3-propanedione<\/strong>.<\/p>\n\n\n\n

The key feature of this mechanism is the formation of a new C\u2013C bond<\/strong> between the \u03b1-carbon of one molecule and the carbonyl carbon of another. The phenyl groups remain untouched during the reaction and are retained in the product.<\/p>\n\n\n\n

This transformation is highly efficient with symmetrical ketones<\/strong> like acetophenone, especially when both starting molecules are identical. Using 2 equivalents<\/strong> ensures both roles \u2014 enolate donor and carbonyl acceptor \u2014 are filled.<\/p>\n\n\n\n

Other options (B, C, D) either include asymmetric ketones (which don\u2019t lead to the symmetrical product) or incorrect stoichiometry (e.g., 1 equivalent in D).<\/p>\n\n\n\n

Therefore, the correct starting material for this retrosynthesis is:<\/p>\n\n\n\n

\n

A. Acetophenone (PhCOCH\u2083), 2 equivalents<\/strong><\/p>\n<\/blockquote>\n\n\n\n

This classic Claisen condensation illustrates the utility of enolate chemistry in forming \u03b2-diketones, key intermediates in pharmaceuticals, ligands, and materials chemistry.<\/p>\n\n\n\n

\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

This is a retrosynthesis arrow. Provide cofrrect starting materials to make this product. == Ph Ph A. Ph (2 equiv.) B. Ph (2 equiv.) C. Ph (2 eqiv.) D. Ph (1 equiv The Correct Answer and Explanation is: \u2705 Correct Answer: A. PhCOCH\u2083 (2 equiv.) Textbook-Style Explanation The product shown is 1,3-diphenyl-1,3-propanedione, a \u03b2-diketone where […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-233280","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/233280","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=233280"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/233280\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=233280"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=233280"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=233280"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}