Reactions of Hydride Complexes of Ruthenium and Osmium with Propargylic Alcohols: Preparation of Chelate Vinyl Derivatives

Vinyl complexes [Ru{η 2 ‐C(=CH 2 )CPh(R)OH(Ru–O)}P 4 ]BPh 4 ( 1 ) [P = P(OEt) 3 ; R = Ph, Me] were prepared by allowing the RuH 2 P 4 hydride to react first with HBF 4 · Et 2 O and then with propargylic alcohol HC≡CCPh(R)OH at low temperature. The complexes were characterised spectroscopically (IR, NMR) and by X‐ray crystal structure determination of the [Ru{η 2 ‐C(=CH 2 )CPh 2 OH(Ru–O)}{P(OEt) 3 } 4 ]BPh 4 ( 1a ) derivative. Related osmium complexes [Os{η 2 ‐C(=CH 2 )CPh(R)OH(Os–O)}P 4 ]BPh 4 ( 2 ) and [Os{η 2 ‐CH=C(H)CPh(R)OH(Os–O)}P 4 ]BPh 4 ( 3 ) [P = P(OEt) 3 ; R = Ph, Me] were obtained by treating the OsH 2 P 4 hydride first with methyl triflate(MeOTf) and then with propargylic alcohol [HC≡CCPh(R)OH]. Spectroscopic data ( 1 H, 31 P, 13 C NMR) suggest the presence of two isomers with four‐ and five‐membered chelate rings of the vinyl ligands. Treatment of vinyl complexes 1 and 2 + 3 with terminal alkynes R 1 C≡CH yielded enynyl derivatives [M{η 3 ‐R 1 C 3 C(H)R 1 }P 4 ]BPh 4 (M = Ru, Os). The allenylidene complex [Os(=C=C=CPh 2 )P 5 ](BPh 4 ) 2 was also prepared by allowing the triflate cation [Os(κ 2 ‐OTf)P 4 ] + to react with propargylic alcohol in CH 2 Cl 2 solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)