Following are the final steps in one industrial synthesis of vitamin A acetate. H,SO, ÓH (1) (2) (3) Pseudoionone B-Ionone (racemic) OH Br Ph P, HBr (4) (5) (racemic) OCCH3 Vitamin A acetate (a) Propose a mechanism for the acid-catalyzed cyclization in Step 1. (b) Propose reagents to bring about Step 2. (c) Propose a mechanism for formation of the phosphonium salt in Step 4. (d) Propose reagents to bring about Step 3. (e) Show how Step 5 can be completed by a Wittig reaction.

Following are the final steps in one industrial synthesis of vitamin A acetate. H,SO, ÓH (1) (2) (3) Pseudoionone B-Ionone (racemic) OH Br Ph P, HBr (4) (5) (racemic) OCCH3 Vitamin A acetate (a) Propose a mechanism for the acid-catalyzed cyclization in Step 1. (b) Propose reagents to bring about Step 2. (c) Propose a mechanism for formation of the phosphonium salt in Step 4. (d) Propose reagents to bring about Step 3. (e) Show how Step 5 can be completed by a Wittig reaction.

Organic Chemistry

9th Edition

ISBN:9781305080485

Author:John E. McMurry

Publisher:John E. McMurry

Chapter11: Reactions Of Alkyl Halides: Nucleophilic Substitutions And Eliminations

Section11.SE: Something Extra

Problem 35MP: One step in the urea cycle for ridding the body of ammonia is the conversion of argininosuccinate to...

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