Enantioselective diethylzinc additions to aldehydes catalyzed by chiral relay ligands

摘要

A new pyrazole ligand system incorporating fluxional chirality was found to catalyze the addition of diethylzinc to aldehydes giving rise to the corresponding secondary alcohol products in excellent yields (74-99%) with moderate to high enantioselectivities (46-93%). The size of the fluxional group on the ligand correlated with the level of enantioselectivity of the product. (C) 2004 Elsevier Ltd. All rights reserved.