Coupling reactions of α-(N-carbamoyl)alkylcuprates with enol triflates derived from cyclic β-keto esters:: A facile approach to γ-carbamoyl-α,β-enoates

alpha-(N-Carbamoylalkyl)cuprates couple with enol triflates derived from carbocyclic and heterocyclic (i.e., piperidinones) beta-keto esters. Product yields are higher with the alkyl(cyano)cuprates [i.e., RCu(CN)Li, 56-93%] than with the dialkylcuprate reagents (i.e., R2CuLi.LiCN). An enol nonaflate works as well as the corresponding enol triflate. A facile synthetic route to gamma-amino alpha,beta-enoates not readily prepared from gamma-keto-alpha,beta-enoates is thus established. The gamma-amino-alpha, beta-enoates, available via N-Boc deprotection, can be cyclized to annulated pyrrolin-2-ones.