Diastereoselective Oxidations of a Thioether Appended with a Neighboring Carboxylic Acid Group

Richard S. Glass, Amorn Petsom, George S. Wilson

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Diastereoselective oxidations of endo acid 5a, 6-endo-(methylthio)bicyclo[2.2.1] heptane-2-endo-carboxylic acid, and endo ester 5b, methyl 6-endo-(methylthio)bicyclo[2.2.1]heptane-2-endo-carboxylate, with the bromine complex of l,4-diazabicyclo[2.2.2]octane in aqueous acetic acid to the corresponding sulfoxides are reported. The relative stereochemistry of the major diastereomeric product obtained by such oxidation of endo acid 5a was unequivocally established by X-ray crystallographic analysis. Endo acid sulfoxide 7a crystallizes in the monoclinic space group P21/ c with a = 8.554 (1) A, b = 8.989 (2) A, c = 12.575 (2) A, β- 98.64 (1)°, and Z = 4. The structure was solved by direct methods. Full-matrix least-squares refinement led to a conventional R factor of 0.038 after several cycles of anisotropic refinement. The predominant sulfoxide formed in the oxidation of endo acid 5a and endo ester 5b with the bromine complex of l,4-diazabicyclo[2.2.2]octane is of the opposite diastereomeric series. This difference in stereochemistry is ascribed to neighboring-group participation in the oxidation of endo acid 5a by the carboxylate moiety. Diastereoselective oxidations of endo acid 5a and endo ester 5b with m-chloroperoxybenzoic acid to the corresponding sulfoxides are reported. The results suggest that the carboxylic acid group does not direct attack by the peracid on the thioether.

Original languageEnglish (US)
Pages (from-to)3537-3541
Number of pages5
JournalJournal of Organic Chemistry
Volume52
Issue number16
DOIs
StatePublished - Aug 1 1987

ASJC Scopus subject areas

  • Organic Chemistry

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