The efficiency of chiral bis(oxazoline)- and azabis(oxazoline)-copper complexes in the enantioselective carbene insertion into CâH bonds of cyclic ethers in homogeneous phase strongly depends on the structure of the substrate. The immobilization on laponite clay by electrostatic interactions not only allows the recovery and reuse of the heterogeneous catalysts, but in some cases also improves enantioselectivity and overall chemoselectivity, making possible reactions that do not take place or lead to low yields in solution, even with the commonly used Rh2[S-DOSP]4 catalyst.
手性双(
噁唑啉)-和双(
噁唑啉)-
铜配合物在均相反应中,对
环醚的C-H键进行手性选择性羰基插入的效率,在很大程度上取决于底物的结构。通过静电相互作用将催化剂固定在拉坡石粘土上,不仅能够回收和重复使用非均相催化剂,在某些情况下还能提高手性选择性和整体
化学选择性,使在溶液中无法发生或导致低产量的反应成为可能,即使使用常用的Rh2[S-
DOSP]4催化剂也是如此。