Stereoselection in the prins-pinacol synthesis of 2,2-disubstituted 4-acyltetrahydrofurans. Enantioselective synthesis of (-)-citreoviral

The condensation of allylic diols with unsymmetrical ketones proceeds with high stereoselection to form 2,2-disubstituted 4-acyltetrahydrofurans when the alpha-substituents of the ketone differ substantially in size. A Prins-pinacol condensation of this type is the central strategic step in an enantioselective synthesis of (-)-citreoviral.