Steric Effects on the Iodide-Induced Elimination of 2- and 3-Methanesulfonyloxy Groups from 5α-Cholestane Derivatives

Abstract

Contrary to earlier reports on closely related compounds, the reaction of all four diastereomers of 5α-cholestane-2,3-diol bismethanesulfonate with sodium iodide gives 5α-cholest-2-ene. The rate of the reaction decreases in the order 2α,3α > 2α 3β » 28,3α ≈ 2β,3β. The reactions of the 5α-cholestan-2- and -3-yl methanesulfonates with sodium iodide were also investigated. The relative reaction rates are explained by considering the steric effects of the substituents.