title: Enantioselective formal [3+3] annulation for the direct construction of bicyclic skeletons with four stereogenic centers.
abstract: An enantioselective formal [3+3] annulation reaction of cyclic ketones with enones has been developed. In the presence of 20 mol % of pyrrolidine-thiourea 1a or N-(pyrrolidin-2-ylmethyl)trifluoromethanesulfonamide 1i, the reactions afford bicyclo [3.3.1] adducts in moderate to good yields with good to high enantioselectivities under mild conditions.
authors.affiliation: The State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 200032 Shanghai, China.
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Cao
authors.forename: Xiu-Li
authors.initials: XL
authors.lastname: Sun
authors.forename: Yan-Biao
authors.initials: YB
authors.lastname: Kang
authors.forename: Yong
authors.initials: Y
authors.lastname: Tang