Chiral P-monodentate phosphoramidite and phosphite ligands for the enantio selective Pd-catalyzed allylic alkylation

The improved synthesis of the chiral phosphoramidite la, based on a biphenol backbone and bearing chiral bis(1-phenyl-ethyl)amine group on the phosphorus atom, is described together with its Pd(II) complex. The chiral complex cis-PdCl2L2 (L = Ia) has been characterized by X-ray crystal structure analysis and spectroscopic data. The series of the chiral P-monodentate phosphoramidite and phosphite ligands was tested in Pd-catalyzed enantioselective allylic substitution of different substrates. In the palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenylallyl acetate with dimethylmalonate, up to 79% ee was achieved with [Pd-2(dba)(3)] x CHCl3 as precatalyst. (c) 2005 Elsevier B.V. All rights reserved.