A reusable, insoluble polymer-bound bis(oxazoline) (IPB-box) for highly enantioselective heterogeneous cyclopropanation reactionsElectronic supplementary information (ESI) available: experimental. See http://www.rsc.org/suppdata/cc/b3/b306483b/
A reusable, insoluble polystyrene-supported bis(oxazoline) was developed, affording e.e.s >90% in the heterogeneous enantioselective cyclopropanation of styrene and 1,1-disubstituted alkenes with ethyl diazoacetate.
Improved Enantioselectivity of Immobilized Chiral Bisoxazolines by Partial Precapping of the Siliceous Mesocellular Foam Support with Trimethylsilyl Groups
作者:Su Seong Lee、Sukandar Hadinoto、Jackie Y. Ying
DOI:10.1002/adsc.200606027
日期:2006.7
Siliceousmesocellularfoams (MCF) were partially surface-modified with trimethylsilyl (TMS) groups prior to the immobilization of chiral tert-butylbisoxazolines. The resulting MCF-supported bisoxazoline-Cu(I) catalyst showed superior enantioselectivity (up to 95 % ee) in asymmetric cyclopropanation, compared to that supported on MCF without TMS precapping. This heterogenized catalyst also exhibited