Synthesis and properties of chiral ruthenium complexes containing O-, S- and P-functionalized Cp-ligands

Novel, functionalized, chiral Cp-ligands with S- and P-donor atoms were des igned. Together with known analogues containing ether side-chains they were complexed to ruthenium for use as chiral Lewis-acid catalysts. In the ethe r complexes [RUCl(eta(5)-C5H4CH2CH2OR) (PPh3)(2)] {R = Me, (1S)-isobomyl, ( 1R)-menthyl, (1R)-fenchyl} the Cp-ligand is only eta(5)-coordinated; all at tempts to provoke a bidentate, Cp/O coordination were unsuccessful. The sul fide complex [RU(eta(5):eta(1)-C5H4CH2CH2S[(1R)-neomenthyl]}(PPh3)(2)][OTf] contains bidentate Cp/S-coordinated ligand, but it is unstable. The stable phosphane complex [RuCl(eta(5):eta(1)-1C(5)H(4)CH(2)CH(Me)PPh2)(PPh3)] exi sts as a 77:23 mixture of diastereomers containing a strongly bidentate Cp/ P ligand. The diastereomers interchange, with Ru-Cl bond cleavage as the ra te-determining step.