Stereochemistry of α-halogeno-sulphoxides. Part 5. Absolute stereochemistry of α-chlorination of benzyl t-butyl sulphoxide

Abstract

α-Halogenation of benzyl t-butyl sulphoxide (2) by electrophilic halogenating agents in pyridine affords a mixture of the diasteroisomeric α-halogenobenzyl t-butyl sulphoxides in the ratio 5:1. In the case of the (R)-sulphoxide (2), chlorination involves selective replacement of the pro-R-hydrogen atom and occurs both with inversion at sulphur and retention at carbon (major path) and with retention at both sulphur and carbon (minor path).