Organocatalytic Asymmetric Nitro-Michael Reaction

Significance

A new organocatalytic asymmetric Michael addition of ketones to nitro-olefins has been developed. Direct addition of ketones 1 to nitro-olefins 2 in the presence of 30 mol% of chiral primary amine 3 provides γ-nitro-ketones in good yields, enantioselectivities, and diastereoselectivities. The reaction presumably proceeds via an enamine intermediate. Cyclic and acyclic alkyl ketones 1 react with aromatic nitro-olefins 2 to give the desired products. Additionally, a transition state to explain the observed relative and absolute configuration is proposed.