26.Synthesis of Thiourea-Oxazolines, a New Class of Chiral S,N-Heterobidentate Ligands: Application in Pd-Catalyzed Asymmetric Bis-methoxycarbonylation of Terminal Olefins

B. Liang, J. Liu, Y. X. Gao, D. X. Shu, K. Wongkhan, Y. Lan, A. Li, A. S. Batsanov, J. A. H. Howard, T. B. Marder*, J. H. Chen*, Z. Yang*

Organometallics, 2007, 26, 4756

A new chiral S,N-heterobidentate thiourea−oxazoline ligand was synthesized and isolated as two atropoisomers (4a, 4b). The ligands were employed in Pd-catalyzed enantioselective bis(alkoxycarbonylation)s of terminal olefins under mild conditions, giving high yields and modest ee values, demonstrating the potential of such ligands for use in Pd-catalyzed carbonylative reactions. Molecular structures of 4a and of the PdCl2 complexes of 4a and 4bhave been determined by single-crystal X-ray diffraction. In both complexes, the ligands exhibit a bidentate S,N bonding mode.