Carbothioamide as Highly Efficient Ligand for Copper-catalyzed Room Temperature Chan-Lam Cross-Coupling Reaction

The catalytic activity of three N, S-donor ligands, viz L1 [2-(4-methoxybenzylidene)-N-phenylhydrazinecarbothioamide], L2 [2,2'-(1,2-diphenylethane-1,2-diylidene) bis(hydrazinecarbothioamide)] and L3 [2-(4-methoxybenzylidene) hydrazinecarbothioamide] has been reported for N-arylation of imidazoles with arylboronic acids in ethanol at room temperature. The method was found to be applicable in N-arylation for a wide range of electronically diverse arylboronic acids with imidazoles having modest to excellent isolated yields. The in situ generated copper(II) complex of the ligand namely, 2-(4-methoxybenzylidene)- N-phenylhydrazinecarbothioamide (L1) was found to be highly efficient homogeneous catalyst for N-arylation reaction.