A practical o-hydroxybenzylamines promoted enantioselective addition of dialkylzincs to aldehydes with asymmetric amplification
作者:Gianni Palmieri
DOI:10.1016/s0957-4166(00)00290-1
日期:2000.8
The addition of dialkylzincs to aldehydes is accelerated considerably by the presence of a catalytic amount of o-hydroxybenzylamine (R,R)-2e to give, after hydrolysis, the corresponding alcohol (S)-9 in good enantiomeric purity. The origins of the enantioselection have been elucidated. A strong positive nonlinear relationship was observed for the reaction enantioselectivity with the use of o-hydroxybenzylamine 2e, which is very accessible through a short stereoselective synthetic route. The enantiomeric purity of the product 9 is much higher than the d.e. of the chiral source 2e, and the rate of the enantioselective catalysis increases considerably with the increase of the d.e. of(R,R)-2e. (C) 2000 Elsevier Science Ltd. All rights reserved.