A divalent thiaruthenacycle complex, cis-Ru[SC 6 H 3 (2-CH 2 )(6-Me)-κ 2 S,C](PMe 3 ) 4 (3), is prepared by the treatment of Ru(η 4 -1,5-COD)(η 6 -1,3,5-COT) (1) with 2,6-dimethylbenzenethiol in the presence of PMe 3 via Ru(η 5 -cyclooctadienyl)(SC 6 H 3 Me 2 -2,6)(PMe 3 ) 2 (2). Exposure of 3 in benzene to H 2 (0.1 MPa) leads to the quantitative formation of cis-RuH(SC 6 H 3 Me 2 -2,6)-(PMe 3 ) 4 (4), which readily turns to 3 at room temperature on evacuation, indicating the reversibility of the reaction. Both forward and backward reactions of this equilibrium are retarded by addition of PMe 3 , suggesting prerequisite prior dissociation of PMe 3 for both reactions. Complex 3 catalyzes selective and facile deuteration of the ortho-methyl and the mercapto groups in 2,6-dimethylbenzenethiol under D 2 .

Treatment of Ru(η 4 -1,5-COD)(η 6 -1,3,5-COT) (1) (COD ) cyclooctadiene (C 8 H 12 )) with a monosubstituted phenol HOC 6 H 4 (R 1 -2) (R 1 ) OMe, CHO, CO 2 Me) in the presence of PMe 3 gives corresponding oxaruthenacycle complexes formulated as cis-On the basis of the reaction profiles monitored by NMR spectroscopy, a mechanism involving a cationic η 5 -cyclooctadienylruthenium(II) intermediate, [Ru(η 5 -C 8 H 11 )(PMe 3 ) 3 ][OAr] (11), followed by the carbon-heteroatom bond cleavage is proposed.

Successive O−C and sp3 C−H bond activation occurs in the reaction of Ru(COD)(COT) (1)/PMe3 with allyl 2,6-xylyl ether to (4). Alternatively, 4 can be obtained by O−H and sp3 C−H bond activation in 2,6-xylenol by 1/PMe3. In both cases, an η3-allyl fragment could be responsible for the sp3 C−H bond activation.

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Insertion of a dimethyl acetylenedicarboxylate (DMAD) into the Ru-C bond in a cycloruthenated complex Ru[OC(6)H(3)(2-CH(2))(6-Me)-kappa(2)O,C](PMe(3))(4) () has been achieved to give a seven-membered oxaruthenacycle Ru[OC(6)H(3){2-CH(2)C(CO(2)Me)[double bond, length as m-dash]C(CO(2)Me)}(6-Me)-kappa(2)O,C](PMe(3))(3) () in 47% yield. The molecular structure of by X-ray analysis shows an agostic interaction between the ruthenium and one of the benzylic methylene protons. Complex shows fluxional behaviour in solution and the variable temperature NMR studies suggest this fluxionality to be responsible for the turnstile rotation of three PMe(3) ligands and the rotation of the alpha-methoxycarbonyl group. Heating of a toluene solution of at 100 degrees C for 2 h results in the 1,3-H shift reaction in to give a kappa(1)O,eta(3)-C,C',C'' allylic complex Ru[OC(6)H(3){2-CHC(CO(2)Me)CH(CO(2)Me)}(6-Me)-kappa(1)O,eta(3)C,C',C''](PMe(3))(3) () (80-90%), whose molecular structure is revealed by X-ray analysis. Acidolyses of and give 2-[(Z)-2',3'-bis(methoxycarbonyl)allyl]-6-methylphenol () (88%) and 2-[(Z)-2',3'-bis(methoxycarbonyl)propenyl]-6-methylphenol () (47%), respectively, and iodolyses of and produce 2,3-bis(methoxycarbonyl)-8-methyl-4H-benzopyran () (24%) and 2,3-bis(methoxycarbonyl)-8-methyl-2H-benzopyran () (48%), respectively.