Palladium(0)-Catalyzed Coupling Reaction of Lithium (α-Carbalkoxyvinyl)cuprates with Organic Halides

Article abstract of DOI:10.1021/jo00238a024

The palladium(0)-catalyzed coupling reaction of lithium (α-carbalkoxyvinyl)(dicyclohexylamido)cuprates and organic halides such as aryl, vinyl, and benzyl halides was investigated.The lithium (α-carbalkoxyvinyl)dicyclohexylamido)cuprates were generated by conjugate addition of organo(dicyclohexylamido)cuprates to α,β-acetylenic esters.The coupling reaction using a Pd(PPh3)4 catalyst proceeded at room temperature to give synthetically useful α,β-substituted acrylates in good yields.The coupling reaction of the (α-carbalkoxyvinyl)(dicyclohexylamido)cuprate derived from a β-unsubstituted α,β-acetylenic ester took place stereoselectively to give an (E)-α,β-substituted acrylate derivative.In the vinyl halide reaction, the stereochemistry of the vinyl halide component is retained in the coupling product.The use of the dicyclohexylamido group as a nontransferable ligand is important.Thus, in the reaction using an (α-carbalkoxyvinyl)(1-hexynyl)cuprate complex, a nonselective coupling involving the 1-hexynyl group took place.