title: Organocatalytic enantio- and diastereoselective conjugate addition to nitroolefins: when β-ketoamides surpass β-ketoesters.
abstract: Our findings on the bifunctional squaramide-catalyzed enantioselective conjugate addition of β-ketoamides to nitroolefins are disclosed. It appears that simple acyclic methylene β-ketoamides, unlike the extensively studied β-ketoesters, afford the products in excellent diastereoselectivities, and maintain high yields and enantioselectivities. Moreover, competition and kinetic studies were conducted to rationalize the observed reactivity and selectivity. The high level of diastereocontrol, along with the amenability of the amide group to postfunctionalization, dramatically increase the synthetic usefulness of the transformation.
authors.affiliation: Aix Marseille Université, Centrale Marseille, CNRS iSm2 UMR 7313, 13397, Marseille (France), Fax: (+33) 491-289-187.
authors.forename: Haiying
authors.initials: H
authors.lastname: Du
authors.forename: Jean
authors.initials: J
authors.lastname: Rodriguez
authors.forename: Xavier
authors.initials: X
authors.lastname: Bugaut
authors.forename: Thierry
authors.initials: T
authors.lastname: Constantieux
keywords: Michael addition; diastereoselectivity; enantioselectivity; ketoamides; nitroolefins