Highly Efficient Ion‐Tagged Catalyst for the Enantioselective Michael Addition of Aldehydes to Nitroalkenes

The ion‐tagged diphenylprolinol silyl ether 6 very efficiently catalyzes the asymmetric Michael addition of aliphatic aldehydes to nitroalkenes with ee of up to>99.5% at low catalyst loadings (0.25–5 mol%) and using only a slight excess of aldehydes (1.2–2 equiv.). This new organocatalyst can be used with the same outstanding efficiency in a wide variety of solvents and reaction conditions.