Phosphine-oxazoline ligands with an axial-unfixed biphenyl backbone: the effects of the substituent at oxazoline ring and P phenyl ring on Pd-catalyzed asymmetric allylic alkylation
These compounds as chiralligands were applied in Pd-catalyzedasymmetricallylicalkylation with high reaction activity and enantioselectivity. Meanwhile, the asymmetric catalytic behavior was affected obviously by the substituent at oxazoline ring and P phenyl ring. The best result, up to 92.3% ee and 99% yield, was obtained with the ligand 3c having two phenyl groups on P and a phenyl group on oxazoline
A Novel Axially Chiral Phosphine-Oxazoline Ligand with an Axis-Unfixed Biphenyl Backbone: Preparation, Complexation, and Application in an Asymmetric Catalytic Reaction
A novel chiral phosphine-oxazoline ligand 3 with an axis-unfixed biphenylbackbone was prepared. This ligand existed as a mixture of two diastereomers in equilibrium in solution. However, when it was coordinated with palladium(II), only one of the two kinds of possible diastereomer complexes with different axialchirality was formed. When this axis-unfixed chiral ligand was used, up to 90% ee was attained
Tropos phosphine-oxazoline ligands have shown interesting coordination behavior and excellent chiral inducing ability in asymmetry catalysis. Here we present a convenient and economic route for the synthesis of this type of ligands. According to this new route, the ligands with different electronic and steric properties have been prepared successfully.