In a series of seven steps, (S)-malic acid is converted to the bromoepoxide shown on the right in 50% overall yield. This synthesis is enantioselective-of the stereoisomers pos- sible for the bromoepoxide, only one is formed. OH COOH A (CgH1405) C (C,H1804) НООС (S)-Malic acid D →E F (C,H,OBr2) Br A bromoepoxide 3. LIAIH4, then H,O 4. TSCI, pyridine 5. NaBr, DMSO Steps/reagents: 1. CH,CH,OH, H+ 6. Н.О, СH,COOН 7. KOH 2. H+ In thinking about the chemistry of these steps, you will want to review the use of dihydropyran as an -OH protecting group (Section 16.7D) and the use of the p-toluenesulfonyl chloride to convert the -OH, a poor leaving group, into a tosylate, a good leaving group non

In a series of seven steps, (S)-malic acid is converted to the bromoepoxide shown on the right in 50% overall yield. This synthesis is enantioselective-of the stereoisomers pos- sible for the bromoepoxide, only one is formed. OH COOH A (CgH1405) C (C,H1804) НООС (S)-Malic acid D →E F (C,H,OBr2) Br A bromoepoxide 3. LIAIH4, then H,O 4. TSCI, pyridine 5. NaBr, DMSO Steps/reagents: 1. CH,CH,OH, H+ 6. Н.О, СH,COOН 7. KOH 2. H+ In thinking about the chemistry of these steps, you will want to review the use of dihydropyran as an -OH protecting group (Section 16.7D) and the use of the p-toluenesulfonyl chloride to convert the -OH, a poor leaving group, into a tosylate, a good leaving group non

Organic Chemistry

9th Edition

ISBN:9781305080485

Author:John E. McMurry

Publisher:John E. McMurry

Chapter19: Aldehydes And Ketones: Nucleophilic Addition Reactions

Section19.SE: Something Extra

Problem 50MP

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