Valine-mediated borane reduction of ketones

摘要

Acetophenone, 3,3-dimethyl-2-butanone, 3-methyl-2-butanone, and 2-penta- none were reduced with (S)-valine-mediated borane in very good yields (86-91/100) giv- ing predominantly alcohols of the (r)-configuration (80,64, 55, and 36/100 ee, respec- tively).