title: New catalysts for the base-promoted isomerization of epoxides to allylic alcohols. Broadened scope and near-perfect asymmetric induction.
abstract: Optically active (1S,3R,4R)-3-[N-(trans-2,5-dialkyl)pyrrolidinyl]methyl-2-azabicyclo-[2.2.1]heptanes were evaluated as catalysts for the enantioselective beta-elimination of meso-epoxides. The (2R,5R)-dimethylpyrrolidinyl-substituted catalyst 4 exhibited exceptionally high enantioselectivity and reactivity, and several substrates were rearranged with enantioselectivities of 98-99% ee. In addition, the use of 4 allowed the first successful, true catalytic rearrangement of the difficult substrates cyclopentene oxide (81%, 96% ee) and (Z)-4-octene oxide (80%, 91% ee).
authors.affiliation: Department of Organic Chemistry, Institute of Chemistry, Uppsala University, Box 531, S-751 21 Uppsala, Sweden.
authors.forename: Sophie K
authors.initials: SK
authors.lastname: Bertilsson
authors.forename: Mikael J
authors.initials: MJ
authors.lastname: Södergren
authors.forename: Pher G
authors.initials: PG
authors.lastname: Andersson