The asymmetric borane reduction of ketones using chiral oxazaborolidine catalysts was reported by E. J. Corey, R. K. Bakshi, and M. Shibata in the 1980s. In this asymmetric reduction, both cyclic and acyclic ketones are converted to chiral alcohols with high enantioselectivity. The chiral oxazaborolidine-type organocatalysts are called CBS catalysts (Product No. D2130 and D2131), named after the developers. TCI also offers toluene solutions (Product No. D5912 and D5911).
References
Highly enantioselective borane reduction of ketones catalyzed by chiral oxazaborolidines. Mechanism and synthetic implications
Reduction of Carbonyl Compounds with Chiral Oxazaborolidine Catalysts: A New Paradigm for Enantioselective Catalysis and a Powerful New Synthetic Method