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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

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posted on 2003-01-09, 00:00 authored by ShengJian Li, R. Karl Dieter
α-(N-Carbamoylalkyl)cuprates couple with enol triflates derived from carbocyclic and heterocyclic (i.e., piperidinones) β-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 γ-amino α,β-enoates not readily prepared from γ-keto-α,β-enoates is thus established. The γ-amino-α,β-enoates, available via N-Boc deprotection, can be cyclized to annulated pyrrolin-2-ones.

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