title: Highly Enantioselective Aza-Michael Reaction between Alkyl Amines and β-Trifluoromethyl β-Aryl Nitroolefins.
abstract: The 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).
authors.affiliation: Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University, Shenzhen Graduate School, Shenzhen, 518055 (China) http://web.pkusz.edu.cn/huang.
authors.forename: Leming
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University, Shenzhen Graduate School, Shenzhen, 518055 (China) http://web.pkusz.edu.cn/huang.
authors.forename: Jiean
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University, Shenzhen Graduate School, Shenzhen, 518055 (China) http://web.pkusz.edu.cn/huang. huangyong@pkusz.edu.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
keywords: N-heterocyclic carbenes; aliphatic amines; asymmetric catalysis; aza-Michael addition; noncovalent catalysis