Direct Conversion of tert-‚-Bromo Alcohols to Ketones with Zinc Sulfide and DMSO

tert-β-Bromo alcohols, derived from simple monoterpene
hydrocarbons, react with zinc sulfide in dimethyl
sulfoxide to afford saturated ketones as the major and
hydroxy ketones as the minor products. The reaction involves initial nucleophilic attack by DMSO on the carbon
attached to the halogen, which is assisted by electrophilic
zinc sulfide. Subsequent Kornblum type oxidation yields the
R-hydroxy ketone. On the other hand, abstraction of proton
‚ to the hydroxyl group followed by an attack of the
neighboring hydroxyl moiety on the sulfur of the imethylsulfoxonium intermediate and its subsequent collapse yields an enol, which tautomerizes to a saturated ketone. The latter pathway is predominantly followed.