{"id":235394,"date":"2025-06-15T10:42:58","date_gmt":"2025-06-15T10:42:58","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=235394"},"modified":"2025-06-15T10:43:00","modified_gmt":"2025-06-15T10:43:00","slug":"in-each-reaction-box-place-the-best-reagent-and-conditions-from-the-list-below-3","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/15\/in-each-reaction-box-place-the-best-reagent-and-conditions-from-the-list-below-3\/","title":{"rendered":"In each reaction box, place the best reagent and conditions from the list below"},"content":{"rendered":"\n


In each reaction box, place the best reagent and conditions from the list below: 1) Ph 2) CH3ONa in CH3OH 3) NaBH4 in EtOH 4) BzHs in THF 5) PCC in CH2Cl2 6) PhCO2H in CH2Cl2 7) O3 in CH2Cl2 8) PhLi in Et2O 9) H2O2\/NaOH 10) H3PO4
In each reaction box, place the best reagent and conditions from the list below: 1) Ph 2) CH3ONa in CH3OH 3) NaBH4 in EtOH 4) BzHs in THF 5) PCC in CH2Cl2 6) PhCO2H in CH2Cl2 7) O3 in CH2Cl2 8) PhLi in Et2O 9) H2O2\/NaOH 10) H3PO4<\/p>\n\n\n\n

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

Correct Reagents:<\/strong><\/p>\n\n\n\n

    \n
  1. PhLi in Et\u2082O<\/strong><\/li>\n\n\n\n
  2. H\u2083PO\u2084, \u0394<\/strong><\/li>\n<\/ol>\n\n\n\n

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

    This synthesis converts cyclohexanone into 1-phenylcyclohex-1-ene in a two-step process. The overall transformation involves the addition of a phenyl group and the formation of a carbon-carbon double bond.<\/p>\n\n\n\n

    Step 1: Nucleophilic Addition of a Phenyl Group<\/strong><\/p>\n\n\n\n

    The first step is to add the phenyl (Ph) group to the cyclohexanone ring. The starting material is a ketone, which has an electrophilic carbonyl carbon. To form a new carbon-carbon bond at this position, a strong carbon-based nucleophile is required. From the provided list, phenyllithium (PhLi in Et\u2082O<\/strong>) is the ideal reagent. The highly polarized carbon-lithium bond in PhLi makes the phenyl group act as a powerful nucleophile. It attacks the carbonyl carbon of cyclohexanone, leading to the formation of a lithium alkoxide intermediate. A subsequent (implied) aqueous workup protonates the alkoxide to yield the tertiary alcohol, 1-phenylcyclohexan-1-ol.<\/p>\n\n\n\n

    Step 2: Dehydration of the Alcohol<\/strong><\/p>\n\n\n\n

    The second step transforms the alcohol intermediate, 1-phenylcyclohexan-1-ol, into the final alkene product, 1-phenylcyclohex-1-ene. This is an elimination reaction, specifically a dehydration. Dehydration of alcohols is effectively carried out by heating them with a strong acid. The reagent H\u2083PO\u2084, \u0394<\/strong> (phosphoric acid with heat) serves this purpose. The acid protonates the hydroxyl (-OH) group, converting it into an excellent leaving group (H\u2082O). A base (such as H\u2082O or the conjugate base H\u2082PO\u2084\u207b) then abstracts a proton from an adjacent carbon, and the electrons from that C-H bond form a new \u03c0 bond, expelling the water molecule. This reaction forms the more stable alkene, where the double bond is conjugated with the phenyl ring, resulting in the desired 1-phenylcyclohex-1-ene product.<\/p>\n\n\n\n

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

    In each reaction box, place the best reagent and conditions from the list below: 1) Ph 2) CH3ONa in CH3OH 3) NaBH4 in EtOH 4) BzHs in THF 5) PCC in CH2Cl2 6) PhCO2H in CH2Cl2 7) O3 in CH2Cl2 8) PhLi in Et2O 9) H2O2\/NaOH 10) H3PO4In each reaction box, place the best reagent […]<\/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-235394","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/235394","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=235394"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/235394\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=235394"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=235394"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=235394"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}