B(C 6 F 5 ) 3 -Catalyzed transfer hydrogenation of esters and organic carbonates towards alcohols with ammonia borane.

Herein, we report an efficient metal-free system for the transfer hydrogenation of esters and carbonates by-passing the otherwise ubiquitous formation of transesterification side-products. The Lewis acid B(C 6 F 5 ) 3 is used as catalyst and ammonia borane as hydrogen donor. This methodology shows broad substrate scope and functional group tolerance in excellent yields at very mild conditions.