title: Gold(I)-catalyzed highly diastereo- and enantioselective alkyne oxidation/cyclopropanation of 1,6-enynes.
abstract: A highly enantioselective oxidative cyclopropanation of 1,6-enynes catalyzed by cationic Au(I)/chiral phophoramidite complexes is presented. The new method provides convenient access to densely functionalized bicyclo[3.1.0]hexanes bearing three contiguous quaternary and tertiary stereogenic centers with high enantioselectivity (up to e.r. 98:2). Control experiments suggest that the quinoline moiety of the β-gold vinyloxyquinolinium intermediate in the reaction plays an important role in promoting good enantioselectivity through a transitional auxiliary effect in the transition state.
authors.affiliation: Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062 (P.R. China).
authors.forename: Deyun
authors.initials: D
authors.lastname: Qian
authors.forename: Haoxiang
authors.initials: H
authors.lastname: Hu
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Tang
authors.forename: Weimin
authors.initials: W
authors.lastname: Ye
authors.forename: Yidong
authors.initials: Y
authors.lastname: Wang
authors.forename: Junliang
authors.initials: J
authors.lastname: Zhang
keywords: alkyne oxidation; carbenoids; cyclopropanation; enantioselectivity; gold