Bis(perfluoroalkyl) phosphino-oxazoline: A modular, stable, strongly π-accepting ligand for asymmetric catalysis

摘要

A new class of stable, strongly π-accepting and modular bis-(perfluoroalkyl)-phosphine-oxazoline ligands (FOX) as CO mimics was prepared. It was demonstrated that these ligands, when coordinated to palladium catalysts, promote the asymmetric alkylation of monosubstituted allyl substrates with excellent regio- and enantioselectivity. Solid and solution structure analysis of the FOX-ligated Pd-allyl intermediate reveals that the combination of relative steric and strong trans influences presented by the P(CF _3) _2 moiety gave rise to the excellent selectivity.