Soluble Polymer-Supported Organocatalysts: Asymmetric Reduction of Imines with Trichlorosilane Catalyzed by an Amino Acid Derived Formamide Anchored to a Soluble Polymer
作者:Andrei V. Malkov、Marek Figlus、Mark R. Prestly、Gouher Rabani、Graeme Cooke、Pavel Kočovský
DOI:10.1002/chem.200901573
日期:2009.9.28
A novel polymeric platform for catalyst immobilization has been developed, featuring inverted solubility pattern: soluble in a nonpolar and insoluble in a polar medium. Asymmetric reduction of imines with Cl3SiH (see scheme), catalyzed by chiral formamide anchored to this soluble polymer, proceeds under homogeneous conditions to give chiral amines in high yields and enantioselectivities (≤91 % ee)
When combined with a chiral phosphate counteranion, a chiral diamine-ligated Ir(III) catalyst displayed excellent enantioselectivities in the asymmetric hydrogenation of a wide range of acyclic imines, affording chiral amines in up to 99% ee.