title: Catalytic asymmetric diels-alder reaction of quinone imine ketals: a site-divergent approach.
abstract: The catalytic asymmetric Diels-Alder reaction of quinone imine ketals with diene carbamates catalyzed by axially chiral dicarboxylic acids is reported herein. A variety of primary and secondary alkyl-substituted quinone derivatives which have not been applied in previous asymmetric quinone Diels-Alder reactions could be employed using this method. More importantly, we succeeded in developing a strategy to divert the reaction site in unsymmetrical 3-alkyl quinone imine ketals from the inherently favored unsubstituted C=C bond to the disfavored alkyl-substituted C=C bond.
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: Hiroki
authors.initials: H
authors.lastname: Nakatsu
authors.forename: Keiji
authors.initials: K
authors.lastname: Maruoka
keywords: Brønsted acids; Diels-Alder reactions; asymmetric catalysis; carboxylic acids; quinones