Highly Enantioselective Aza‐Michael Reaction between Alkyl Amines and β‐Trifluoromethyl β‐Aryl Nitroolefins

Abstract

AbstractThe aza‐Michael addition reaction is a vital transformation for the synthesis of functionalized chiral amines. Despite intensive research, enantioselective aza‐Michael reactions with alkyl amines as the nitrogen donor have not been successful. We report the use of chiral N‐heterocyclic carbenes (NHCs) as noncovalent organocatalysts to promote a highly selective aza‐Michael reaction between primary alkyl amines and β‐trifluoromethyl β‐aryl nitroolefins. In contrast to classical conjugate‐addition reactions, a strategy of HOMO‐raising activation was used. Chiral trifluoromethylated amines were synthesized in high yield (up to 99 %) with excellent enantioselectivity (up to 98 % ee).