Cp2VCl2-catalyzed meso-selective pinacol coupling reaction of aldimines inthe presence of chlorosilane and zinc metal

A catalytic reductive coupling of aldimines was achieved by using a catalys t Cp2VCl2/PhMe2SiCl/Zn system. The influence of the catalyst, chlorosilane, co-reductant, solvent, and temperature on both the yield and diastereosele ctivity of the coupling products was investigated in detail. As a result, t he present Cp2VCl2-catalyzed reductive coupling of aldimines in the presenc e of PhMe2SiCl and zinc metal provided the corresponding 1,2-diamines in go od yield with high meso selectivity (up to 92% meso), while the reductive c oupling of aldehydes, ketones, and aldimines by the hitherto known catalyti c methods leads to the preferential formation of dl isomers of the coupling products.