Transition metal complexes with the C1-symmetric diphosphines (R)-(R)-3-benzyl-2,4-bis(diphenylphosphino)pentane and (R)-(R)-3-benzyl(p-sulphonate)-2,4-bis(diphenylphosphino)pentane sodium salt.: Applications to enantioselective catalysis in different phase systems

The C-1-symmetric diphosphine (R)-(R)-3-benzyl-2,4-bis(diphenylphosphino)pentane [(R)-(R)-BDPBzP] has been employed, in combination with Ru(II), Rh(I), Ir(I) and Pd(II) ions, in a variety of homogeneous asymmetric reactions spanning from the hydrogenation of dimethyl itaconate, methyl 2-acetamidocinnamate, 2-methylquinoxaline, methyl pyruvate and dihydro-4,4dimethyl-2,3-furandione, to the hydroboration of styrene, to the allylic alkylation of (rac)-(E)-3-acetoxy- ,3-diphenyl-1-propene with dimethyl malonate. The aqueous-biphase hydrogenation of dimethyl itaconate has been accomplished with Rh(I) and Ir(I) complexes containing the monosulphonated derivative (R)-(R)-3-benzyl(p-sulphonate)-2,4-bis(diphenyphosphino)pentane [(R)-(R)-BDPBzPSO(3)(-)] Irrespective of the phase variation system, the catalyst precursors generally feature good activity and good to modest enantioselectivity. (C) 2001 Elsevier Science B.V. All rights reserved.