Enantioselective synthesis of α-silylamines by Meerwein-Ponndorf-Verley-type reduction of α-silylimines by a chiral lithium amide.
Meerwein-Ponndorf-Verley-type reduction of N-tosylsilylimines with chiral lithium amide 2 affords α-silylamines in high enantioselectivity. Since the enantioselectivity observed was inconsistent with our previously proposed chairlike six-membered transition structure, we performed density functional theory (DFT) calculations on transition states leading to (S)- and (R)-7a and (S)- and (R)-7e using an N-phenylsulfonyl derivatives 12 and 13 as model systems. Results of the calculations showed that the structures are considerably deformed from the chairlike form with steric repulsions between the 1'-methylene group and the imine-carbon substituents playing an important role in the control of the enantioselectivity.
Department of Synthetic Organic Chemistry, Institute of Biomedical and Health Sciences, Hiroshima University , 1-2-3 Kasumi, Minami-Ku, Hiroshima 734-8553, Japan.
Yasuhiro
Y
Kondo
Michiko
M
Sasaki
Masatoshi
M
Kawahata
Kentaro
K
Yamaguchi
Kei
K
Takeda
D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D008094:Lithium / Q000737:chemistry*; D008958:Models, Molecular; D017646:Organosilicon Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D000577:Amides; D017646:Organosilicon Compounds; D008094:Lithium