Diastereospecific Gas/Solid Additions with Cholesterol Derivatives

Abstract

Crystals of cholesterol and some of its esters, e.g. 1, add the reactive gases HBr and Br2 both quantitatively and economically. These reactions, which are very simple to carry out, lead to the kinetically controlled diastereospecific formation of the crystalline adducts, e.g. 2, without intermediate melting.