Phosphine-phosphite ligands in the palladium-catalyzed asymmetric allylic alkylation: Electronic and steric effects

asymmetric allylic alkylation of rac-1,3-diphenyl-2-propenyl acetate catalyzed by the palladium-complexes of phosphine-phosphite ligands with 1,1'-binaphthyl- or 1,1'-octahydrobinaphthyl-moiety is reported. The roles of (i) the tether length in directly analogous phosphine-phosphite ligands, (ii) the stereogenic elements in the backbone of PC3OP type of ligands, and (iii) the BINOL moiety in the activities and enantioselectivities of the catalysts are studied. The applicability of these ligands was also evaluated in ethylene and propylene carbonates as green solvents obtaining up to 69% ees with good activity. By using directly analogous phosphine-phosphite ligands the catalytic activity increases steadily with the length of the backbone and with the basicity of the phosphine moiety. (c) 2013 Elsevier B.V. All rights reserved.