{"id":224726,"date":"2025-06-03T12:04:26","date_gmt":"2025-06-03T12:04:26","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=224726"},"modified":"2025-06-03T12:04:28","modified_gmt":"2025-06-03T12:04:28","slug":"which-reagents-are-appropriate-to-carry-out-the-conversion-shown","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/03\/which-reagents-are-appropriate-to-carry-out-the-conversion-shown\/","title":{"rendered":"Which reagents are appropriate to carry out the conversion shown"},"content":{"rendered":"\n

Which reagents are appropriate to carry out the conversion shown? o conc. H_(2)SO_(4),2. HBr;2. NaOH;2. TsC(l)\/() pyridine; 2.CH_(3)CH_(2)COH Search Which reagents are appropriate to carry out the conversion shown? OH 1.conc.HSO4,2 0 O.Na 1.HBr2 00 ONa 1.NaOH;2. ONa O1.TsCI\/pyridine;2.CH3CHCOH Search I0 40<\/p>\n\n\n\n

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

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

Correct Answer:<\/strong><\/h3>\n\n\n\n

1. TsCl\/pyridine; 2. CH\u2083CH\u2082CO\u207b (ethoxide in ethanol)<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation<\/strong><\/h3>\n\n\n\n

The transformation shown is a substitution reaction<\/strong>, where the hydroxyl group (\u2013OH) in the starting compound is replaced by a propionate group<\/strong> (\u2013O\u2013COCH\u2082CH\u2083), resulting in an ester<\/strong>. Specifically, we are converting a secondary alcohol<\/strong> into an ester<\/strong> using a two-step mechanism.<\/p>\n\n\n\n

\n\n\n\n

Step-by-Step Mechanism:<\/strong><\/h3>\n\n\n\n

Step 1: Tosylation using TsCl\/Pyridine<\/strong><\/h4>\n\n\n\n
    \n
  • TsCl (tosyl chloride) reacts with the alcohol in the presence of pyridine (a base) to form a tosylate ester (R\u2013OTs)<\/strong>.<\/li>\n\n\n\n
  • Tosylates are excellent leaving groups<\/strong>, much better than \u2013OH.<\/li>\n\n\n\n
  • The reaction mechanism involves activation of the hydroxyl group, converting it into a better leaving group without disturbing the stereochemistry of the carbon center.<\/li>\n<\/ul>\n\n\n\n

    Step 2: Nucleophilic Substitution using CH\u2083CH\u2082CO\u207b<\/strong><\/h4>\n\n\n\n
      \n
    • The ethyl carboxylate anion (ethoxide from propionic acid) acts as a nucleophile<\/strong>.<\/li>\n\n\n\n
    • It displaces the tosyl group via an SN2 reaction<\/strong>, forming an ester.<\/li>\n\n\n\n
    • Since this is an SN2 reaction on a secondary carbon, the inversion of configuration might be considered, but tosylate formation maintains the configuration until the backside attack by the nucleophile, resulting in overall inversion<\/strong> of stereochemistry. However, the stereochemistry is not the focus here\u2014formation of the ester<\/strong> is.<\/li>\n<\/ul>\n\n\n\n
      \n\n\n\n

      Why Other Options Are Incorrect:<\/strong><\/h3>\n\n\n\n
        \n
      1. conc. H\u2082SO\u2084:<\/strong> Acidic conditions typically lead to dehydration or ether formation, not esterification with a carboxylate nucleophile.<\/li>\n\n\n\n
      2. HBr:<\/strong> This would lead to substitution with Br\u207b, not ester formation.<\/li>\n\n\n\n
      3. NaOH:<\/strong> Would not activate \u2013OH to become a good leaving group or promote ester formation.<\/li>\n<\/ol>\n\n\n\n
        \n\n\n\n

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

        The best method is tosylation followed by nucleophilic attack with a carboxylate anion, which is achieved by TsCl\/pyridine; then CH\u2083CH\u2082CO\u207b<\/strong>. This efficiently forms the ester shown in the product.<\/p>\n\n\n\n

        \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

        Which reagents are appropriate to carry out the conversion shown? o conc. H_(2)SO_(4),2. HBr;2. NaOH;2. TsC(l)\/() pyridine; 2.CH_(3)CH_(2)COH Search Which reagents are appropriate to carry out the conversion shown? OH 1.conc.HSO4,2 0 O.Na 1.HBr2 00 ONa 1.NaOH;2. ONa O1.TsCI\/pyridine;2.CH3CHCOH Search I0 40 The Correct Answer and Explanation is: Correct Answer: 1. TsCl\/pyridine; 2. CH\u2083CH\u2082CO\u207b (ethoxide […]<\/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-224726","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/224726","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=224726"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/224726\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=224726"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=224726"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=224726"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}