title: Desymmetrizing asymmetric ring expansion of cyclohexanones with α-diazoacetates catalyzed by chiral aluminum Lewis acid.
abstract: Chiral aluminum Lewis acid catalyst composed of Me(3)Al and 3,3'-bis(trimethylsilyl)-BINOL in a 2:1 ratio was found to promote novel catalytic asymmetric ring expansion of cyclohexanone with α-substituted α-diazoacetates to give seven-membered rings with an all-carbon quaternary center. Application of this strategy to 4-substituted cyclohexanones opened up a novel way for the catalytic desymmetrizing asymmetric construction of cycloheptanones bearing remote α,δ-chiral centers.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Naganawa
authors.forename: Keiji
authors.initials: K
authors.lastname: Maruoka