Nitroalkylation and nitroalkenylation reactions of γ-lactone enolates. A facile ring switch from polysubstituted γ-lactones to polysubstituted γ-lactams

Michael addition of lithium enolates of γ-butyrolactone and α-methyl-γ-butyrolactone to (E)-1-nitropropene , (E)-β-nitrostyrene and (E)-2-nitro-1-phenylpropene is described. Reactions of the lithium enolate of with and occurred with high diasteroselectivity (80 and 92% d.e., respectively). Reactions of the zinc enolate of with two β-nitroenamines and two methylthio-substituted 1-amino-2-nitro-1,3-dienes were also examined. Catalytic reduction of the nitroalkylated and nitroalkenylated products allowed the achievement of functionalized γ-lactams and/or cyclic hydroxamic acids.