{"id":192886,"date":"2025-02-18T10:10:48","date_gmt":"2025-02-18T10:10:48","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=192886"},"modified":"2025-02-18T10:10:49","modified_gmt":"2025-02-18T10:10:49","slug":"bromination-of-an-alkene-by-n-bromosuccinimide-nbs-in-the-presence-of-light-or-peroxide-is-a-radical-reaction-and-produces-an-allylic-bromide","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/18\/bromination-of-an-alkene-by-n-bromosuccinimide-nbs-in-the-presence-of-light-or-peroxide-is-a-radical-reaction-and-produces-an-allylic-bromide\/","title":{"rendered":"Bromination of an alkene by N-bromosuccinimide (NBS) in the presence of light or peroxide is a radical reaction and produces an allylic bromide"},"content":{"rendered":"\n<p>Bromination of an alkene by N-bromosuccinimide (NBS) in the presence of light or peroxide is a radical reaction and produces an allylic bromide. For the following bromination of 3-methylcyclopentene, select the allylic bromides from the set at the right that would be products of the reaction.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/02\/image-942.png\" alt=\"\" class=\"wp-image-192887\"\/><\/figure>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\"><strong>The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n<p>In the reaction of 3-methylcyclopentene with N-bromosuccinimide (NBS) in the presence of light or peroxide, a radical mechanism takes place. The reaction proceeds via the formation of a bromine radical (Br\u2022), which abstracts a hydrogen atom from the allylic positions of the alkene. This generates an allylic radical, which can then combine with the bromine radical to form the product.<\/p>\n\n\n\n<p>To understand the products, let&#8217;s break down the structure of 3-methylcyclopentene. The double bond in 3-methylcyclopentene is between the 2 and 3 carbons of the cyclopentene ring. The 3-methyl group is attached to carbon 3, which is next to the double bond. The allylic positions that can undergo abstraction of a hydrogen atom (to form the allylic radical) are the carbons adjacent to the double bond: C1 (on the left of the double bond) and C4 (on the right of the double bond).<\/p>\n\n\n\n<p>When the bromine radical abstracts a hydrogen atom from one of these positions, it generates an allylic radical. There are two possible positions for the formation of the allylic radical:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>C1 radical<\/strong>: If the hydrogen is abstracted from C1, the resulting allylic radical would be stabilized by resonance with the double bond.<\/li>\n\n\n\n<li><strong>C4 radical<\/strong>: If the hydrogen is abstracted from C4, the resulting allylic radical would also be stabilized by resonance with the double bond.<\/li>\n<\/ul>\n\n\n\n<p>Both C1 and C4 radicals are equally stabilized due to the conjugation with the double bond, so both are viable sites for the bromination to occur.<\/p>\n\n\n\n<p>The final products are the two possible allylic bromides:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Bromination at C1<\/strong>: The bromine atom attaches to C1, producing 1-bromo-3-methylcyclopentene.<\/li>\n\n\n\n<li><strong>Bromination at C4<\/strong>: The bromine atom attaches to C4, producing 4-bromo-3-methylcyclopentene.<\/li>\n<\/ul>\n\n\n\n<p>These are the two possible products of the reaction, as the reaction is a radical process that allows for the formation of bromine at either of the two allylic positions (C1 or C4).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Bromination of an alkene by N-bromosuccinimide (NBS) in the presence of light or peroxide is a radical reaction and produces an allylic bromide. For the following bromination of 3-methylcyclopentene, select the allylic bromides from the set at the right that would be products of the reaction. The Correct Answer and Explanation is : In the [&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-192886","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/192886","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=192886"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/192886\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=192886"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=192886"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=192886"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}