Asymmetric organocatalytic cascade Michael/acyl transfer reaction of 2-hydroxychalcones with alpha-nitroketones

摘要

A highly enantioselective (84-97% ee) cascade Michael/acyl transfer reaction of alpha-nitroketones to a wide range of 2-hydroxychalcones was established in the presence of a bifunctional squaramide. Although aliphatic alpha-nitroketones were revealed to be a class of challenging substrates with unsatisfactory reactivity or enantioselectivity by previous reports, good isolated yields and excellent enantiopurities have been achieved via our catalytic protocol. gamma-Nitroketones created by this new methodology were versatile building blocks possessing profound further synthetic utility. (C) 2019 Elsevier Ltd. All rights reserved.