Carbon-oxygen and carbon-sulfur bond activation of vinyl esters, ethers and sulfides by low valent ruthenium complexes

[Ru(cod)(cot)] (1) (cod: 1,5-cyclooctadiene, cot: 1,3,5-cyclooctatriene) re acts with phenyl vinyl ether and vinyl sulfides in the presence of the bide ntate depe ligand affording the zerovalent (eta(2)-vinyl ether or sulfide)r uthenium(0) complexes, [Ru(eta(2)-C2H3YR)(cod)(depe)] [RY=PhO (2a), PhS (2b ), PhCH2S (2c), EtS (2d), Me2CHS (2e), depe: 1,2-bis(diethylphosphino)ethan e]. Whereas the vinyl ether or sulfide ligand is selectively displaced in 2 a, 2d and 2e by monodentate phosphines giving [Ru(cod)(depe)L] [L=PMe3 (3a) , PMe2Ph (3b)], partial exchange reactions of either the vinyl sulfide liga nd or cod take place for 2b and 2c affording 3a and b and [Ru(eta(2)-C2H3SR )(depe)(L)(2)] [L=PMe3, R=Ph (4a), L=PMe2Ph, R=Ph (4b); L=PMe3, R=CH2Ph (4c )]. The intermolecular C-S bond cleavage takes place in 4a promoted by MeI to form [Ru(I)(eta(1)-C2H3)(depe)(PMe3)(2)] 5 with liberation of MeSPh. On the other hand, reactions of 1 with vinyl carboxylates in the presence of t ertiary phosphines such as PMe3, PEt3 or depe give a series of (eta(1)-viny l)ruthenium(II) complexes cis-[Ru(eta(1)-C2H3)(eta(1)-OCOR')(PMe3)(4)] [R'= Me (6a), Et (6b), Bu-t (6c), Ph (6d)], mer-[Ru(eta(1)-C2H3)(eta(2)-OCOR')(P Et3)(3)] [R'=Me (7a), Et (7b), Bu-t (7c), Ph (7d), C(Me)=CH2 (7e)], trans-[ Ru(eta(1)-C2H3)(eta(1)-OCOR')(depe)(2)] [R'=Me (8a), Et (8b), Bu-t (8c), Ph (8d), C(Me)=CH2 (8e)]. The structures of 2a, 2b, 3a, and 8a have been dete rmined by X-ray crystallography. A mechanism including prior co-ordination of the vinylic moiety has been proposed for the C-O bond cleavage reaction on ruthenium(0).