Some applications of nickel boride as a desulphurising agent. An improved route to triterpene 2-enes

Abstract

Optimum conditions are defined for the desulphurisation of ethylene dithioacetals with nickel boride. Normally a mixture of saturated and unsaturated products is formed. Nickel boride is inferior to Raney nickel for the desulphurisation of thiophens. Hemithioacetals are rapidly cleaved by nickel boride, allowing regeneration of the ketone. Triterpene 2-enes are obtained in excellent yield from 3-ketones by desulphurisation of intermediate benzyl thio(enol ether)s with either nickel boride or Raney nickel.