Conjugate addition reactions of α-aminoalkylcuprates with α,β-alkenyl-, α,β-alkynyl-, α,β-allenyl-, and α,β-γ,δ-dienyl carboxylic acid derivatives, nitriles, and sulfoxides

Article abstract of DOI:10.1021/jo0056038

α-Aminoalkylcuprates prepared from α-lithio carbamates and CuCN·2LiCl participate in 1,4-addition reactions with α,β-unsaturated esters, thiol esters, imides, and nitriles in poor to excellent yields depending upon the electron-withdrawing substituent and the substitution pattern of the unsaturated substrate. These reagents also undergo conjugate addition reactions with α,β-alkynyl esters, sulfoxides, and nitriles and with α,β-β,γ-unsaturated allenyl esters. Excellent stereocontrol is achieved in the conjugate additions of α-aminoalkylcuprates to the allenyl esters, while poor stereoselectivity results in the conjugate additions to the alkynyl derivatives. Deprotection and cyclization of the alkynyl adducts affords pyrrolin-2-ones, while similar treatment of the allenyl adducts affords 4-alkylidine- pyrrolidin-2-ones and pyrrolizidinones.