Enantioselective diethylzinc addition to aldehydes via chiral, non-racemic β-hydroxysalicylhydrazone catalysts
摘要:
A series of tridentate beta-hydroxysalicylhydrazone ligands have been prepared from (1R,2S)-ephedrine and (1R,2S)-norephedrine and tested in the catalytic asymmetric addition of dietbylzine to aldehydes. The isolated chemical yields of the addition products ranged from 50% to 84%. The reactions exhibited very good enantioselectivity with enantiomeric ratios ranging from 89:11 to 96:4. (C) 2008 Elsevier Ltd. All rights reserved.