A new axially chiral phosphine-sulfonamide ligand was prepared via a chiral component (R)-2-amino-2'-diphenyl-phosphinyl-1,1'-binaphthyl, which was conveniently synthesized through a new route involving hydrolysis of (R)-2-cyano-2'-phosphinyl-1,1'-binaphthyl followed by Hofmann rearrangement of the amide group. The new ligand was found to be very efficient in copper-catalyzed enantio selective conjugate addition of diethylzinc to acyclic enones such as benzylideneacetones, providing very high enantioselectivity up to 99% ee. (C) 2004 Elsevier Ltd. All rights reserved.