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J Org Chem
; 68(8): 3232-7, 2003 Apr 18.
Article
in English
| MEDLINE
| ID: mdl-12688795
ABSTRACT
The dioxirane-mediated epoxidation of alkenes in the presence of supported alpha-fluorotropinones 5 and 9 has been evaluated. The catalysts anchored onto silica supports 5 have shown comparable activity with respect to the homogeneous counterpart 10 and good stability on recycling. In the second part of this paper the enantiomerically enriched alpha-fluorotropinone 4 was anchored onto both mesoporous MCM-41 and amorphous KG-60 silicas. The chiral-supported catalysts promoted the stereoselective epoxidation of several trans-substituted and trisubstituted alkenes with ee values up to 80% and were perfectly reusable with the same performance for at least three catalytic cycles.