Thiazole-based non-symmetric NNC–palladium pincer complexes as catalytic precursors for the Suzuki–Miyaura C–C coupling
We report an efficient synthesis of new non-symmetric pincer palladacycles 2a–i, containing a [NNC]-tridentate ligand formed by a hydrazone and a thiazolyl moiety as sources of N-donor atoms. These catalytic precursors were tested in the Suzuki–Miyaura cross coupling reaction using a variety of aryl boronic acids with aryl bromides or chlorides using water as solvent. Complex 2a displays the best catalytic performance under aerobic conditions, affording the coupling products in good to high yields. In all cases, the cross-coupling reaction was conducted under IR irradiation, allowing a decrease in the reaction time.