Synthesis of Thiourea−Oxazolines, a New Class of Chiral S,N-Heterobidentate Ligands: Application in Pd-Catalyzed Asymmetric Bis(methoxycarbonylation) of Terminal Olefins
作者:Bo Liang、Jing Liu、Ying-Xiang Gao、Kittiya Wongkhan、Dong-Xu Shu、Yu Lan、Ang Li、Andrei S. Batsanov、Judith A. H. Howard、Todd B. Marder、Jia-Hua Chen、Zhen Yang
DOI:10.1021/om700311x
日期:2007.9.1
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 4b have been determined by single-crystal X-ray diffraction. In both complexes, the ligands exhibit a bidentate S,N bonding mode.