{"id":190779,"date":"2025-02-13T08:24:06","date_gmt":"2025-02-13T08:24:06","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=190779"},"modified":"2025-02-13T08:24:09","modified_gmt":"2025-02-13T08:24:09","slug":"grignard-reaction","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/13\/grignard-reaction\/","title":{"rendered":"Grignard Reaction"},"content":{"rendered":"\n

Grignard Reaction Scheme MeMgBr OH N C Me Me H THF, 0 \u00b0C<\/p>\n\n\n\n

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

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

The given reaction scheme involves a Grignard reaction<\/strong>, where methylmagnesium bromide (MeMgBr)<\/strong> is used as the Grignard reagent in the presence of tetrahydrofuran (THF<\/strong>) at 0\u00b0C<\/strong>. Let’s break down the reaction step by step.<\/p>\n\n\n\n

\n\n\n\n

Step 1: Identifying the Reactants<\/strong><\/h3>\n\n\n\n
    \n
  • Grignard Reagent (MeMgBr):<\/strong> This is a strong nucleophile and a strong base, known for attacking electrophilic carbonyl compounds.<\/li>\n\n\n\n
  • Substrate:<\/strong> The given structure appears to have an amide (-N-C=O)<\/strong> functional group.<\/li>\n\n\n\n
  • Solvent:<\/strong> THF<\/strong>, a common solvent for Grignard reactions, stabilizes the organomagnesium reagent.<\/li>\n\n\n\n
  • Temperature:<\/strong> 0\u00b0C suggests controlled reaction conditions to avoid side reactions.<\/li>\n<\/ul>\n\n\n\n
    \n\n\n\n

    Step 2: Understanding the Reaction Mechanism<\/strong><\/h3>\n\n\n\n
      \n
    1. Attack on the Amide Carbonyl:<\/strong><\/li>\n<\/ol>\n\n\n\n
        \n
      • Grignard reagents typically react with esters, ketones, and aldehydes<\/strong> to form alcohols.<\/li>\n\n\n\n
      • However, with amides<\/strong>, Grignard reagents do not<\/strong> directly yield alcohols. Instead, they replace the amide nitrogen with two equivalent alkyl groups.<\/li>\n\n\n\n
      • The lone pair on nitrogen delocalizes, making the carbonyl carbon less reactive than aldehydes or ketones, but it can still react under excess Grignard conditions.<\/li>\n<\/ul>\n\n\n\n
          \n
        1. Formation of a Ketone Intermediate:<\/strong><\/li>\n<\/ol>\n\n\n\n
            \n
          • The first equivalent of MeMgBr<\/strong> attacks the carbonyl carbon, causing elimination of NR\u2082<\/strong> and forming a ketone<\/strong> intermediate.<\/li>\n<\/ul>\n\n\n\n
              \n
            1. Further Reaction to a Tertiary Alcohol:<\/strong><\/li>\n<\/ol>\n\n\n\n
                \n
              • The ketone undergoes a second attack by another MeMgBr<\/strong> equivalent, leading to a tertiary alcohol<\/strong> after acidic workup.<\/li>\n<\/ul>\n\n\n\n
                \n\n\n\n

                Step 3: Final Product<\/strong><\/h3>\n\n\n\n

                The reaction produces a tertiary alcohol<\/strong> at the carbon center that was originally the amide carbonyl. The structure of the product will have:<\/p>\n\n\n\n

                  \n
                • Three alkyl groups attached to the central carbon.<\/li>\n\n\n\n
                • A hydroxyl (-OH) group in place of the original amide.<\/li>\n<\/ul>\n\n\n\n

                  Thus, the final product is 2-methyl-2-pentanol<\/strong> (tertiary alcohol with three alkyl groups attached to the hydroxyl carbon).<\/p>\n","protected":false},"excerpt":{"rendered":"

                  Grignard Reaction Scheme MeMgBr OH N C Me Me H THF, 0 \u00b0C The Correct Answer and Explanation is : The given reaction scheme involves a Grignard reaction, where methylmagnesium bromide (MeMgBr) is used as the Grignard reagent in the presence of tetrahydrofuran (THF) at 0\u00b0C. Let’s break down the reaction step by step. Step […]<\/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-190779","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/190779","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=190779"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/190779\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=190779"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=190779"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=190779"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}