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.