Iminium salt-mediated catalytic asymmetric epoxidation

P.C.B. Page, B.R. Buckley, D. Barros, H. Heaney, A.J. Blacker, B.A. Marples, Non-aqueous iminium salt mediated catalytic asymmetric epoxidation, Tetrahedran 62 (2006) 6607. 

Yang and co-workers have suggested that the inherent difficulties in the preparation/isolation of unstable exocyclic iminium salts can be overcome by in situ formation of the catalytic species from chiral pyrrolidines and aldehydes. The catalytic asymmetric epoxidation of phenylcyclohexene and dihydronaphthalene mediated by the iminium salt derived from pyrrolidine 67 and aldehyde 68 has been examined (Scheme 27) <20010L2587>. 

SCHEME 5.21 The standard conditions applied for catalytic asymmetric epoxidation mediated by Oxone and iminium salts. 

V.K. Aggarwal, M.F. Wang, Catalytic asymmetric synthesis of epoxides mediated by chiral iminium salts, Chem. Commun. (1996) 191. 

P.C.B. Page, G. A. Rassias, D. Barros, A. Ardakani, D. Bethell, E. Merifield, New organocatalysis for the asymmetric catalytic epoxidation of alkenes mediated by chiral iminium salts, Synlett 4 (2002) 580. 

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