Highly Diastereoselective and Irreversible Aldol Reactions of N-Sulfonylimidates

A mild method for the aldolization of N -sulfonylimidates was developed. The reaction proceeds in excellent diastereoselectivity to provide a range of useful β-hydroxyimidates in high yield. The innate reversibility of the reaction is suppressed by the use of a titanium complex as a Lewis acid.