l-Piperazine-2-carboxylic acid derived N-formamide as a highly enantioselective Lewis basic catalyst for hydrosilylation of N-aryl imines with an unprecedented substrate profile

[reaction: see text] l-Piperazine-2-carboxylic acid derived N-formamides have been developed as highly enantioselective Lewis basic catalysts for the hydrosilylation of N-aryl imines with trichlorosilane. The arene sulfonyl group on N4 was found to be critical for the high enantioselectivity of the catalyst. High isolated yields (up to 99%) and enantioselectivities (up to 97%) were obtained for a broad range of substrates, including aromatic and aliphatic ketimines, particularly those with R(2) as relatively bulky alkyl groups.