{"id":192242,"date":"2025-02-17T12:04:51","date_gmt":"2025-02-17T12:04:51","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=192242"},"modified":"2025-02-17T12:04:54","modified_gmt":"2025-02-17T12:04:54","slug":"electrophilic-addition-of-br2-to-isoprene-2-methyl-1-3-hutadiene-yields-the-following-product-mixture","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/17\/electrophilic-addition-of-br2-to-isoprene-2-methyl-1-3-hutadiene-yields-the-following-product-mixture\/","title":{"rendered":"Electrophilic addition of Br2 to isoprene (2-methyl-1, 3-hutadiene) yields the following product mixture"},"content":{"rendered":"\n

Electrophilic addition of Br2 to isoprene (2-methyl-1, 3-hutadiene) yields the following product mixture: Of the 1, 2-addition products, explain why 3, 4-dibromo-3-methyl-1-butene (21 %) predominates over 3, 4-dibromo-2-mcthyl-1-butene(3%).<\/p>\n\n\n\n

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

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

The electrophilic addition of Br\u2082 to isoprene (2-methyl-1,3-butadiene) leads to a mixture of products due to the formation of carbocations in the reaction mechanism. The two major possible 1,2-addition products are 3,4-dibromo-3-methyl-1-butene<\/strong> and 3,4-dibromo-2-methyl-1-butene<\/strong>. The reason why 3,4-dibromo-3-methyl-1-butene<\/strong> predominates over 3,4-dibromo-2-methyl-1-butene<\/strong> (21% vs. 3%) is due to the stability of the carbocation intermediate formed during the reaction.<\/p>\n\n\n\n

Here’s the breakdown of the process:<\/p>\n\n\n\n

    \n
  1. Electrophilic addition mechanism<\/strong>:<\/li>\n<\/ol>\n\n\n\n
      \n
    • The Br\u2082 molecule undergoes homolytic cleavage, creating a Br\u207a ion (the electrophile) and a Br\u207b ion.<\/li>\n\n\n\n
    • The Br\u207a ion attacks the electron-rich double bond of isoprene (2-methyl-1,3-butadiene), forming a carbocation intermediate.<\/li>\n<\/ul>\n\n\n\n
        \n
      1. Carbocation formation<\/strong>:<\/li>\n<\/ol>\n\n\n\n
          \n
        • In the case of 3,4-dibromo-3-methyl-1-butene<\/strong>, the intermediate carbocation is formed at the C-2<\/strong> position (the carbon adjacent to the double bond), leading to a 3-methyl-1-butyl cation<\/strong>.<\/li>\n\n\n\n
        • For 3,4-dibromo-2-methyl-1-butene<\/strong>, the carbocation intermediate forms at C-4<\/strong>, resulting in a secondary carbocation<\/strong>.<\/li>\n<\/ul>\n\n\n\n
            \n
          1. Stability of the carbocations<\/strong>:<\/li>\n<\/ol>\n\n\n\n
              \n
            • The carbocation formed at C-2<\/strong> in the 3,4-dibromo-3-methyl-1-butene<\/strong> product is tertiary<\/strong> (adjacent to the methyl group on C-3), which is significantly more stable than the secondary<\/strong> carbocation formed at C-4<\/strong> in the 3,4-dibromo-2-methyl-1-butene<\/strong> product.<\/li>\n\n\n\n
            • More stable carbocations are more likely to form, leading to a higher concentration of 3,4-dibromo-3-methyl-1-butene<\/strong> in the product mixture.<\/li>\n<\/ul>\n\n\n\n

              Thus, the 3,4-dibromo-3-methyl-1-butene<\/strong> product predominates because the carbocation intermediate involved in its formation is more stable than the one for 3,4-dibromo-2-methyl-1-butene<\/strong>, making the reaction pathway leading to the former more favorable.<\/p>\n\n\n\n

              Now, let me generate an image for you that visualizes this concept.<\/p>\n\n\n\n

              Here is the diagram illustrating the electrophilic addition of Br\u2082 to isoprene, showing the two possible products and the formation of carbocations at C-2 and C-4. As discussed, the more stable tertiary carbocation formed at C-2 leads to the predominance of 3,4-dibromo-3-methyl-1-butene<\/strong> over the other product. Let me know if you need further clarification!<\/p>\n","protected":false},"excerpt":{"rendered":"

              Electrophilic addition of Br2 to isoprene (2-methyl-1, 3-hutadiene) yields the following product mixture: Of the 1, 2-addition products, explain why 3, 4-dibromo-3-methyl-1-butene (21 %) predominates over 3, 4-dibromo-2-mcthyl-1-butene(3%). The Correct Answer and Explanation is : The electrophilic addition of Br\u2082 to isoprene (2-methyl-1,3-butadiene) leads to a mixture of products due to the formation of carbocations […]<\/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-192242","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/192242","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=192242"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/192242\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=192242"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=192242"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=192242"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}