{"id":229404,"date":"2025-06-08T07:00:22","date_gmt":"2025-06-08T07:00:22","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=229404"},"modified":"2025-06-08T07:00:27","modified_gmt":"2025-06-08T07:00:27","slug":"draw-the-major-product-of-this-reaction","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/08\/draw-the-major-product-of-this-reaction\/","title":{"rendered":"Draw the major product of this reaction"},"content":{"rendered":"\n

Draw the major product of this reaction. Ignore inorganic byproducts.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

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

The given reaction is a Knoevenagel condensation<\/strong>, a base-catalyzed reaction between an aldehyde (here, acrolein) and a compound with active methylene groups (here, 1,3-cyclohexanedione) in the presence of KOH (a base). Let’s break this down step by step.<\/p>\n\n\n\n

\n\n\n\n

Reactants:<\/strong><\/h3>\n\n\n\n
    \n
  1. Acrolein (CH2=CH\u2013CHO):<\/strong> An \u03b1,\u03b2-unsaturated aldehyde.<\/li>\n\n\n\n
  2. 1,3-Cyclohexanedione:<\/strong> A cyclic diketone with two ketone groups on a six-membered ring at the 1 and 3 positions.<\/li>\n\n\n\n
  3. Base: KOH<\/strong><\/li>\n<\/ol>\n\n\n\n
    \n\n\n\n

    Mechanism Overview:<\/strong><\/h3>\n\n\n\n
      \n
    1. Enolate Formation:<\/strong>
      Under basic conditions (KOH), one of the acidic \u03b1-hydrogens of 1,3-cyclohexanedione is abstracted, forming a resonance-stabilized enolate ion.<\/li>\n\n\n\n
    2. Nucleophilic Attack:<\/strong>
      The enolate ion acts as a nucleophile and attacks the electrophilic carbonyl carbon of acrolein (specifically the aldehyde carbon), forming a \u03b2-hydroxy intermediate.<\/li>\n\n\n\n
    3. Dehydration (Elimination):<\/strong>
      This intermediate loses a water molecule (facilitated by the base), leading to formation of a carbon-carbon double bond \u2013 forming an \u03b1,\u03b2-unsaturated system<\/strong> (a conjugated enone).<\/li>\n<\/ol>\n\n\n\n
      \n\n\n\n

      Major Product:<\/strong><\/h3>\n\n\n\n

      The major product<\/strong> is a conjugated enone<\/strong>, specifically formed by condensation of 1,3-cyclohexanedione with acrolein. The new double bond is between the \u03b1-carbon of 1,3-cyclohexanedione and the \u03b2-carbon of acrolein. The product looks like this:<\/p>\n\n\n\n

      Structure:<\/strong><\/p>\n\n\n\n

        \n
      • A six-membered ring (cyclohexane) with keto groups at positions 1 and 3.<\/li>\n\n\n\n
      • A side chain attached at position 2 of the ring: CH=CH\u2013CHO (but now dehydrated to CH=CH\u2013), forming a conjugated enone.<\/li>\n<\/ul>\n\n\n\n

        So, the final structure is:
        2-(3-oxoprop-1-enyl)cyclohexane-1,3-dione<\/strong><\/p>\n\n\n\n

        This Knoevenagel condensation product is stabilized via resonance in the enone system and conjugation with the carbonyl groups.<\/p>\n\n\n\n

        \n\n\n\n

        Conclusion:<\/strong><\/h3>\n\n\n\n

        This is a classic example of the Knoevenagel condensation where:<\/p>\n\n\n\n

          \n
        • A nucleophilic enolate (from 1,3-cyclohexanedione) reacts with an electrophilic carbonyl compound (acrolein).<\/li>\n\n\n\n
        • KOH promotes enolate formation and drives the reaction to dehydration.<\/li>\n\n\n\n
        • The product is a stable \u03b1,\u03b2-unsaturated carbonyl compound with extended conjugation, enhancing stability.<\/li>\n<\/ul>\n\n\n\n
          \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

          Draw the major product of this reaction. Ignore inorganic byproducts. The Correct Answer and Explanation is: The given reaction is a Knoevenagel condensation, a base-catalyzed reaction between an aldehyde (here, acrolein) and a compound with active methylene groups (here, 1,3-cyclohexanedione) in the presence of KOH (a base). Let’s break this down step by step. Reactants: […]<\/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-229404","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/229404","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=229404"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/229404\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=229404"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=229404"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=229404"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}