An ortho-Substituted BIPHEP Ligand and Its Applications in Rh-Catalyzed Hydrogenation of Cyclic Enamides
摘要:
[GRAPHICS]An ortho-substituted BIPHEP ligand, o-Ph-hexaMeO-BIPHEP (1), is designed and synthesized. Compared with chiral biaryl phosphines without ortho substituents such as BINAP and MeO-BIPHEP, o-Ph-hexaMeO-BIPHEP shows higher enantioselectivities in Rh-catalyzed hydrogenation of cyclic enamides.
Development of a new class of C1-symmetric bisphosphine ligands for rhodium-catalyzed asymmetric hydrogenation
作者:Qian Dai、Wei Li、Xumu Zhang
DOI:10.1016/j.tet.2008.03.110
日期:2008.7
A newclass of C1-symmetric bisphosphine ligands with three hindered quadrants have been obtained through facile synthesis from chiral BINOL derivatives. Their rhodium complexes have exhibited high enantioselectivities (up to 98% ee) in the asymmetric hydrogenation of various unsaturated prochiral olefins, providing an efficient catalytic system for the enantioselective synthesis of chiral amino acids
Enamides were efficiently prepared via a novel Rh/C-catalyzed direct hydroacylation of ketoximes. Up to 88% isolated yield of enamides were obtained with this method. Subsequent asymmetric hydrogenation of the enamides with Rh/DuanPhos complex gave the corresponding chiral amine in excellent enantioselectivities (up to 99.7% ee).
An <i>ortho</i>-Substituted BIPHEP Ligand and Its Applications in Rh-Catalyzed Hydrogenation of Cyclic Enamides
作者:Wenjun Tang、Yongxiang Chi、Xumu Zhang
DOI:10.1021/ol0258435
日期:2002.5.1
[GRAPHICS]An ortho-substituted BIPHEP ligand, o-Ph-hexaMeO-BIPHEP (1), is designed and synthesized. Compared with chiral biaryl phosphines without ortho substituents such as BINAP and MeO-BIPHEP, o-Ph-hexaMeO-BIPHEP shows higher enantioselectivities in Rh-catalyzed hydrogenation of cyclic enamides.