Design, synthesis and applications of a ketone reduction catalyst containing a phosphinamide combined with a dioxaborolidine unit

Article abstract of DOI:10.1016/0957-4166(96)00400-4

We have designed and prepared a catalyst for the asymmetric reduction of ketones which combines a phosphinamide and a boron-containing heterocyclic ring. The former group acts to direct and activated the borane, whilst the latter provides a well defined position for location of the ketone. The resulting reduction therefore takes place in a well-defined stereochemical environment. Enantiomeric excesses of up to 59%, in a predictable absolute sense, were achieved. Evidence that O- co-ordination of borane is important in the reduction mechanism is also presented. Copyright (C) Elsevier Science Ltd.