Nonsimple relationships between the P∗-chiral diamidophosphite and the arylphosphine moieties in Pd-catalyzed asymmetric reactions: combinatorial approach and P,P∗-bidentate phosphine-diamidophosphites

A small family of P,P∗-bidentate C1-symmetric ligands containing 1,3,2-diazaphospholidine rings with stereogenic phosphorus atoms has been prepared. Palladium catalytic systems with these phosphine-diamidophosphites afforded 95% and 63% ees in asymmetric allylic substitution and desymmetrization processes, respectively. The influence of the nature of both the phosphine and diamidophosphite moieties of these compounds on the enantioselectivity is discussed. The ‘mixed-ligand approach’ in Pd-catalyzed asymmetric allylation with participation of some new P∗-monodentate diamidophosphites and PPh3 is also considered.