A novel o-quinodimethane strategy for an active metabolite of vitamin D3. A total synthesis of 25-hydroxy Windaus-Grundmann ketone

Abstract

A highly diastereoselective total synthesis of 25-hydroxy Windaus-Grundmann ketone ( 2) was achieved via a novel regiocontrolled CC bond formation by an intramolecular epoxide ring opening reaction of the bissulfonyl epoxide ( 19) as a key step, which was derived stereoselectively by the thermolysis of olefinic benzocyclobutene ( 8) as a key step.