Epoxidation of lanost-9(11)-enes. The effect of a β-carbonyl group upon the stereochemistry of epoxidation
Abstract
m-Chloroperbenzoic acid epoxidation of 3β-acetoxylanost-9(11)-en-7-one afforded two isomeric epoxides, the β-isomer being the major product. This result is in contrast with the epoxidation of other 9(11)-olefins having no carbonyl group. It is interpreted in terms of the ‘directive effect’ of the β-carbonyl group which generally influences the steric course of the epoxidation of β-oxo-olefins and is of polar character.