{"id":184959,"date":"2025-01-21T19:43:05","date_gmt":"2025-01-21T19:43:05","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=184959"},"modified":"2025-01-21T19:43:08","modified_gmt":"2025-01-21T19:43:08","slug":"consider-the-reaction-of-the-cyclopentanone-derivative-shown-below","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/21\/consider-the-reaction-of-the-cyclopentanone-derivative-shown-below\/","title":{"rendered":"Consider the reaction of the cyclopentanone derivative shown below"},"content":{"rendered":"\n<p>Consider the reaction of the cyclopentanone derivative shown below. i) Na<\/p>\n\n\n\n<p>+<\/p>\n\n\n\n<p>OCH<\/p>\n\n\n\n<p>2<\/p>\n\n\n\n<p>?<\/p>\n\n\n\n<p>CH<\/p>\n\n\n\n<p>3<\/p>\n\n\n\n<p>?<\/p>\n\n\n\n<p>,CH<\/p>\n\n\n\n<p>3<\/p>\n\n\n\n<p>?<\/p>\n\n\n\n<p>CH<\/p>\n\n\n\n<p>2<\/p>\n\n\n\n<p>?<\/p>\n\n\n\n<p>OH,25<\/p>\n\n\n\n<p>\u00b0<\/p>\n\n\n\n<p>C ? ii) CH<\/p>\n\n\n\n<p>3<\/p>\n\n\n\n<p>?<\/p>\n\n\n\n<p>! Draw the structure for the major product formed in this reaction. The cyclopentanone starting material has been provided as a starting point.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\">The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>The reaction involves the <strong>cyclopentanone derivative<\/strong> undergoing an aldol condensation reaction in the presence of a strong base (sodium methoxide, NaOCH3\\text{NaOCH}_3) in methanol (CH3CH2OH\\text{CH}_3\\text{CH}_2\\text{OH}) as the solvent. After that, a methylation step occurs (CH3I\\text{CH}_3I).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Reaction Steps:<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Deprotonation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Sodium methoxide (NaOCH3\\text{NaOCH}_3) acts as a strong base, abstracting an alpha proton from the cyclopentanone derivative. This generates an enolate ion stabilized by resonance with the ketone group.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Aldol Addition<\/strong>:\n<ul class=\"wp-block-list\">\n<li>The enolate ion acts as a nucleophile and attacks another molecule of the cyclopentanone derivative at its electrophilic carbonyl carbon. This results in the formation of a \u03b2-hydroxy ketone intermediate.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Aldol Condensation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Under the reaction conditions (heat, basic medium), the \u03b2-hydroxy ketone intermediate undergoes dehydration, forming an \u03b1,\u03b2-unsaturated ketone. This product contains a conjugated double bond system, which is thermodynamically stable.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Methylation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>In the second step, methyl iodide (CH3I\\text{CH}_3I) reacts with the \u03b1,\u03b2-unsaturated ketone. The methylation likely occurs at the enolate ion, formed by deprotonating the \u03b1-hydrogen of the conjugated system. This leads to the final product: a methylated \u03b1,\u03b2-unsaturated ketone.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Major Product:<\/h3>\n\n\n\n<p>The major product is an <strong>\u03b1-methyl-\u03b1,\u03b2-unsaturated ketone derivative<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation:<\/h3>\n\n\n\n<p>This reaction illustrates typical aldol condensation followed by an alkylation step. The first step, catalyzed by a strong base, generates an enolate ion. The subsequent aldol addition and condensation form the conjugated double bond system. The final methylation step introduces a methyl group to the alpha position of the unsaturated ketone.<\/p>\n\n\n\n<p>This sequence is driven by the reactivity of the enolate ion and the electrophilic carbon of the carbonyl group, making aldol condensation a key step in organic synthesis for forming C\u2013C bonds and generating conjugated systems.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Consider the reaction of the cyclopentanone derivative shown below. i) Na + OCH 2 ? CH 3 ? ,CH 3 ? CH 2 ? OH,25 \u00b0 C ? ii) CH 3 ? ! Draw the structure for the major product formed in this reaction. The cyclopentanone starting material has been provided as a starting point. [&hellip;]<\/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-184959","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/184959","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=184959"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/184959\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=184959"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=184959"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=184959"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}