Two-step synthesis of alpha,beta-unsaturated gamma-amino acid esters via N-heterocyclic carbene catalyzed [4+2] cycloaddition of enals and nitroso compounds

An efficient strategy for the synthesis of various of α,β-unsaturated γ-amino acid esters has been established employing N-heterocyclic carbene catalyzed [4+2] cycloadditions of β-methyl enals and aromatic nitroso compounds to afford 1,2-oxazin-6-ones in good yields. A subsequent acid-catalyzed esterification under ring opening yields the γ-amino enoates in good yields. © Georg Thieme Verlag Stuttgart.New York.