Kinetic resolution in Pd-catalyzed allylic substitution using the helical PHelix ligand

The chiral helical diphosphine 2,1 5-bis(diphenylphosphino)-hexahelicene (PHelix) is an excellent ligand in palladium catalyzed kinetic resolution involving allylic substitution. Depending upon the substrate, enantioselectivities (ee) of up to 99% are observed. Although formally a diphosphine, PHelix appears not to undergo chelation, which means that it behaves as a chiral monophosphine. (C) 2000 Published by Elsevier Science S.A. All rights reserved.