CHIRAL SYNTHESIS VIA ORGANOBORANES .41. THE UTILITY OF B-CHLORODIISOPINOCAMPHEYLBORANE FOR A GENERAL-SYNTHESIS OF ENANTIOMERICALLY PURE-DRUGS

A general approach to the synthesis of enantiomerically pure alpha-phe nyl amino alcohols via the asymmetric reduction of alpha-phenyl haloal kyl ketones or alpha-phenyl aminoalkyl ketones with B-chlorodiisopinoc ampheylborane is described. Using this approach, an improved synthesis of a potential antipsychotic, luorophenyl)-4-(2-pyrimidinyl)-1-pipera zinebutanol in greater than or equal to 98% ee, and the broncholdilato r -phenethyl)-4-(3-hydroxy-3-phenylpropyl)piperazine (eprozinol) in gr eater than or equal to 99% ee is achieved. (C) 1995 Wiley-Liss, Inc.