Direct asymmetric alpha-amination of cyclic ketones catalyzed by siloxyproline.
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.
Hayashi
Yujiro
Y
Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. hayashi@ci.kagu.tus.ac.jp
Aratake
Seiji
S
Imai
Yoshinaga
Y
Hibino
Kazuhiro
K
Chen
Qi-Yin
QY
Yamaguchi
Junichiro
J
Uchimaru
Tadafumi
T
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
D007659:Ketones; C526940:siloxyproline; D014867:Water; D011392:Proline