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Free keywords:
asymmetric catalysis; phosphites; phosphonites; transition metals; enantioselectivity
Abstract:
Starting from commercially available (S)-1-(2- bromophenyl)ethanol, novel phosphite/phosphonite ligands have been prepared in which a BINOL moiety is attached to each phosphorus centre. The four diasteromeric ligands were tested in Cu-catalysed conjugate addition of Et2Zn, Pd-catalysed allylic substitution and Rh-catalysed hydrogenation. Very different results regarding activity and enantioselectivity as a function of the particular diastereomer were observed. (C) 2002 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.