Preparation of highly optically pure homochiral sulfide-containing alcohols via oxazaborolidine-catalyzed asymmetric borane reduction of ketones

Highly optically pure homochiral 1‐(4‐alkylthiophenyl) alcohols were prepared efficiently and practically via the oxazaborolidine‐catalyzed asymmetric borane reduction of prochiral ketones in toluene at 25°C. The coordination of the sulfur atom in the ketones to the boron atom in the catalyst and borane can be inhibited under these reduction conditions. Chirality 16:341–346, 2004. © 2004 Wiley‐Liss, Inc.