Synthesis and stereochemical studies of the chiral ruthenium complexes [Ru(η-C5H5)(S)dpompyr-PP′X] [dpompyr = N-diphenylphosphino-2-(diphenylphosphinoxymethyl)pyrrolidine, X = H or Cl]. Crystal structure of [(S)Ru(η-C5H5)(S)dpompyr-PP′Cl]

A simple procedure for the preparation of [(S)Ru(η-C5H5)(S)dpompyr-PP′H] [dpompyr = N-diphenylphosphino-2-(diphenylphosphinoxymethyl)pyrrolidine] from [Ru3(CO)12] is described. The hydride reacts stereospecifically with chloroform or carbon tetrachloride to give [(S)Ru(η-C5H5)(S)dpompyr-PP′Cl] whose structure is reported. The crystals are monoclinic, space group P21 with a = 11.076(2), b = 10.908(2), c = 12.825(3) Å, β = 92.26(2), and Z = 2. The structure was solved by the heavy-atom method and refined to R = 0.0322 using 2 306 diffractometer data with I > 3σ(I). Synthesis of this chloro-complex from [Ru(η-C5H5)(PPh3)2Cl] and (S)dpompyr proceeds with only modest diastereoselectivity whereas reduction of [(S)Ru(η-C5H5)(S)dpompyr-PP′Cl] using LiAlH4 regenerates 88% [(S)Ru(η-C5H5)(S)dpompyr-PP′H]. Mechanisms are proposed to explain the observed diastereoselectivities. Circular dichroism and 1H, 13C, and 31P n.m.r. spectra of all new compounds are also reported.