The borane reduction of aryl methyl ketones catalyzed by MerCO [( 1R,2S,3R)-3-mercaptocamphan-2-ol] produced I-aryl ethyl alcohols in 92% e.e. at 50 degrees C in toluene. Significant temperature and solvent effects were observed in this reaction. (C) 1999 Elsevier Science Ltd. All rights reserved.