OPTICALLY-ACTIVE TRANSITION-METAL COMPLEXES - SYNTHESIS AND STEREOCHEMICAL STUDIES ON HALF-SANDWICH CHIRAL RUTHENIUM COMPLEXES [RU(ETA-5-C5H5)(P-P)X] - CRYSTAL-STRUCTURE OF [(S)-RU(ETA-5-C5H5)(BPPM)CL]A AND OF [(R)-RU(ETA-5-C5H5)(PROLOPHOS)I]B

The preparation of [(S)-Ru(eta5-C5H5)(BPPM)Cl], 4a [BPPM = (2S,4S)-(-)-tert-butoxycarbonyl-4-diphenylphosphino-2-(diphenylphosphinomethyl)pyrrolidine] from Ru3(CO)12 and the stereochemistry of halogen-exchange reactions on [(S)-Ru(eta5-C5H5)(Prolophos)Cl], 5a [Prolophos = (S)-(-)-N-(diphenylphosphino)-2-(diphenylphosphinoxymethyl)pyrrolidine] to give the corresponding bromo and iodo complexes, are described. The structure of [(S)-Ru(eta5-C5H5)(BPPM)Cl], 4a, and of [(R)-Ru(eta5-C5H5)(Prolophos)I], 7a, are reported. Crystals of 4a are orthorhombic, space group P2(1)2(1)2(1) with a = 9.524(3), b = 19.439(2), c = 20.396(3) angstrom, Z = 4, R = 0.040 for 2542 observed reflections. Crystals of 7a are monoclinic, space group P2(1), with a = 8.886(2), b = 15.929(1), c = 11.884(1) angstrom, beta = 110.87(1), Z = 2, R = 0.019 for 3313 observed reflections. All the reactions unequivocally occur with retention of configuration at the ruthenium atom.