Aspects of stereochemistry. Part XIX. Directive effects of remote substituents on the alkaline epoxidation of 3-oxo-Δ4-steroids

Abstract

3-Oxo-Δ⁴-steroids that do not contain polar substituents react with alkaline hydrogen peroxide to give 3-oxo-4β,5β-epoxides. Up to 30% of the α-epoxy-ketone is formed when the steroid contains a polar group at C-17 or beyond; this result is discussed in terms of electrostatic interactions between the polar substituent and the anionic transition states. Polar substituents at C-11 show stronger directive effects.