已证明具有n -C 8 F 17氟标签的可回收和可重复使用的(S)二苯基吡咯啉甲硅烷基醚I有机催化剂可促进多种醛与芳基和烷基取代的硝基烯烃的不对称迈克尔加成反应,并具有极好的水平实现对映和非对映选择性。可以通过氟固相萃取方便地回收催化剂I,然后再使用(最多8个循环),而不会显着降低该方法的催化活性和立体选择性。
Recoverable Fluorous CBS Methodology for Asymmetric Reduction of Ketones
摘要:
An operationally simple and recoverable fluorous CBS methodology was developed. The in situ-generated fluorous oxazaborolidine efficiently catalyzed the reduction of ketones with high enantioselectivity and reactivity. The subsequent recycling of the fluorous prolinol precatalyst was achieved by fluorous solid-phase extraction.
CBS Reductions with a Fluorous Prolinol Immobilized in a Hydrofluoroether Solvent
摘要:
A fluorous prolinol precatalyst bearing only 34 fluorine atoms has been immobilized in the hydrofluoroether solvent HFE-7500. The,CBS reduction of acetophenone proceeded rapidly, in high yield and in high ee in the absence of any organic solvent. The organic product was stripped from the HFE-7500 phase with a polar solvent, and the HFE-7500 phase was reused "as is" with satisfactory results through eight runs. This process is an attractive prototype for the large-scale use, recovery, and reuse of fluorous organocatalysts.