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

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 PdCl 2 complexes of 4a and 4b have been determined by single-crystal X-ray diffraction. In both complexes, the ligands exhibit a bidentate S,N bonding mode.