Highly enantioselective Mannich reactions with α-aryl silyl ketene acetals and imines.

Mannich reactions with chiral silicon Lewis acid activated acylhydrazones and α-aryl silyl ketene acetals and α-aryl,α-alkyl silyl ketene imines proceed efficiently and with good to excellent levels of both diastereoselectivity and enantioselectivity. The reactions provide access to α-aryl,ß-hydrazido esters and α-aryl,α-alkyl,ß-hydrazido nitriles, which are valuable analogs of ß-amino acids.