NaBH 4 Reduction of Ketones in the Solid State

Without solvent, merely by rubbing the solid reactants in an agate mortar, it was possible to reduce more than just simple ketones with NaBH4; even regio- and enantioselective reductions could be achieved when inclusion complexes were used. The hydroxyketones 2 and 4, which are of interest as synthetic building blocks, were prepared from the ketones 1 and 3, respectively.