title: Direct asymmetric alpha-amination of cyclic ketones catalyzed by siloxyproline.
abstract: trans-tert-Butyldimethylsiloxy-L-proline displays greater catalytic activity and affords higher enantioselectivity than the parent proline in the alpha-amination reaction of carbonyl compounds with azodicarboxylate. A quantum mechanical calculation reveals the structure of the transition state. In the presence of a catalytic amount of siloxyproline and water (3-9 equiv), alpha-amino carbonyl derivatives, which are important synthetic intermediates, are obtained in good yield and with excellent enantioselectivity.
authors.affiliation: Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. hayashi@ci.kagu.tus.ac.jp
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Seiji
authors.initials: S
authors.lastname: Aratake
authors.forename: Yoshinaga
authors.initials: Y
authors.lastname: Imai
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hibino
authors.forename: Qi-Yin
authors.initials: QY
authors.lastname: Chen
authors.forename: Junichiro
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Uchimaru
mesh_terms: D000586:Amination; D002384:Catalysis; D003500:Cyclization; D007659:Ketones / Q000737:chemistry*; D008745:Methylation; D008958:Models, Molecular; D015394:Molecular Structure; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry
chemical_list: D007659:Ketones; C526940:siloxyproline; D014867:Water; D011392:Proline