Asymmetric oxazaborolidine-catalyzed reduction of prochiral ketones with N-tert-butyl-N-trimethylsilylamine–borane

Employing N-tert-butyl-N-trimethylsilylamine-borane (1) as the borane source and 5–10% (R)-Me-CBS (2), the oxazaborolidine-catalyzed reduction of representative aryl and aliphatic ketones was carried out obtaining the corresponding alcohols (3) in 83–89% isolated yields and 69–98% ee.