Chemoselective Reduction of Tertiary Amides to Amines Catalyzed by Triphenylborane.

Triphenylborane (BPh3 ) was found to catalyze the reduction of tertiary amides with hydrosilanes to give amines under mild condition with high chemoselectivity in the presence of ketones, esters, and imines. N,N-Dimethylacrylamide was reduced to provide the α-silyl amide. Preliminary studies indicate that the hydrosilylation catalyzed by BPh3 may be mechanistically different from that catalyzed by the more electrophilic B(C6 F5 )3 .