Stereochemistry of Alkylation of Cyclic β-Ketosulfoxides. II. Alkylations of 2-Methylbenzo [b] thiophen-3 (2H)-one 1-Oxide

Abstract

Alkylation of the carbanion derived from 2-methylbenzo [b] thiophen-3 (2H)-one 1-oxide (3) with alkyl halide was found to occur cis to the S-O bond with high stereoselectivity. A pyramidal structure is proposed for the intermediary carbanion based on the results of carbon-13 nuclear magnetic resonance spectroscopy.