A modular approach to a new class of monodentate chiral phosphorus ligands and their application in enantioselective copper-catalysed conjugate additions of diethylzinc to cyclohexenone

A new family of chiral phosphorus ligands (5) for use in enantioselective catalysis have been synthesised. The ligands contain the electron-poor bis(sulfonyl)diazaphospholidine moiety and possess a highly modular structure which is well suited to the synthesis of a library. A small library (23 members) of ligands 5 was prepared and tested in the enantioselective copper-catalysed conjugate addition of diethylzinc to cyclohexenone. Complete conversions were obtained with enantiomeric excesses (ee) of up to 75%. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.