title: Enantioselective epoxidation of alkenes catalyzed by 2-fluoro-N-carbethoxytropinone and related tropinone derivatives.
abstract: Several alpha-substituted N-carbethoxytropinones have been evaluated as catalysts for asymmetric epoxidation of alkenes with Oxone, via a dioxirane intermediate. alpha-Fluoro-N-carbethoxytropinone (2) has been studied in detail and is an efficient catalyst which does not suffer from Baeyer-Villiger decomposition and can be used in relatively low loadings. This ketone was prepared in enantiomerically pure form using chiral base desymmetrization of N-carbethoxytropinone. Asymmetric epoxidation catalyzed by 2 affords epoxides with up to 83% ee. Among other derivatives tested, the alpha-acetoxy derivative 7 affords the highest enantioselectivities.
authors.affiliation: School of Chemistry, University of Nottingham, Nottingham NG7 2RD, U.K. a.armstrong@ic.ac.uk
authors.forename: Alan
authors.initials: A
authors.lastname: Armstrong
authors.forename: Ghafoor
authors.initials: G
authors.lastname: Ahmed
authors.forename: Belen
authors.initials: B
authors.lastname: Dominguez-Fernandez
authors.forename: Barry R
authors.initials: BR
authors.lastname: Hayter
authors.forename: J Steven
authors.initials: JS
authors.lastname: Wailes