Enantioselective Synthesis of α-Silylamines by Meerwein–Ponndorf–Verley-Type Reduction of α-Silylimines by a Chiral Lithium Amide
作者:Yasuhiro Kondo、Michiko Sasaki、Masatoshi Kawahata、Kentaro Yamaguchi、Kei Takeda
DOI:10.1021/jo500441a
日期:2014.4.18
Meerwein-Ponndorf-Verley-type reduction of N-tosylsilylimines with chiral lithium amide 2 affords alpha-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.