Electronic and steric control in regioselective addition reactions of organolithium reagents with enaldimines.
A reaction mode of imines derived from naphthalene-1-carbaldehyde and acyclic alpha,beta-unsaturated aldehydes with organolitium reagents was dependent on the characteristic nature of a substituent on the imine nitrogen atom. An imine having an electron-withdrawing aryl group on the nitrogen atom behaves as a 1,2-directing imine toward organolithium reagents. In contrast, an imine bearing an alkyl or a bulky aryl group favors 1,4-addition of organolithium reagents. Electronic and steric tuning of a substituent on the imine nitrogen atom for a reaction mode was rationalized on the basis of molecular orbital calculations.
Tomioka
K
K
Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Sakyo-ku, Kyoto 606-8501, Japan. tomioka@pharm.kyoto-u.ac.jp
Shioya
Y
Y
Nagaoka
Y
Y
Yamada
K
K