Palladium-catalysed asymmetric allylic substitution: a ligand design incorporating steric and electronic effects

Abstract

Enantiomerically pure ligands containing a 4,5-dihydrooxazole moiety tethered to an auxiliary sulfur or phosphorus donor have been prepared. These ligands have been exploited for palladium-catalysed asymmetric allylic substitution, providing enantioselectivities of 40–96% ee. The origin of the enantioselectivity in the catalytic reaction is discussed in terms of the steric and electronic influences provided by the ligand.