Ruthenium complexes trans effect

The complexes frans-[Ru(NH3)4 P(OR)3 2] and trans-[Ru(NH3)4 P(OEt)3 P(OR)3 ], with R = methyl, isopropyl, or butyl, aquate to give a monophosphite product with rate constants which vary little with the nature of the complex or solvent composition (up to 80% ethanol). The results support the dissociative mechanism previously proposed for the triethyl phosphite complex. Trans effects are here dominated by 7T acceptor properties of these phosphite ligands. Trans effects in substitution in bis-ligand ruthenium (and iron) phthalocyanine complexes follow the order... 

Several ruthenium complexes bearing chiral Schiff s base ligands have been published. RuL(PPh3)(H20)2], complex C (Fig. 11), with PhIO produced (S)-styrene oxide in 80% ee [61]. Chiral Schiff s base complex D was examined using molecular oxygen with aldehyde, with or without 2,6-dichloropyridine N-oxide as an axial ligand. Styrene oxide was produced in up to 24% ee[62]. A chiral bis(oxazolinyl)pyridine ruthenium complex E with iodosylbenzene diacetate PhI(OAc)2 produced (lS,2S)-fra s-stilbene oxide in 74% ee [63]. Similarly, chiral ruthenium bis(bipyridine) sulfoxide complex F [64] was effective in combination with PhI(OAc)2 as an oxidant and resulted in in 33% ee for (R,R) trans-stilbene oxide and 94% ee for (R,R) trans-/i-Me-styrene (after 75 h at 25 °C). 

Propenyl Ethers and Unsaturated Cyclic Ethers Propenyl ethers (CH3—CH=CH—OR R = ethyl, isobutyl, etc. cis- and trans-isomers) and 3,4-dihydrofuran are linear and cyclic a,/3-unsaturated ethers, that can be regarded as / -substituted vinyl ether derivatives. For these monomers a few controlled/living cationic polymerizations have been reported. The HI/I2 system is generally effective for both linear and cyclic monomers [181,182,183], whereas a recent study by Nuyken indicates that the IBVE-HI adduct coupled with nBu4NC104 is suited for 3,4-dihydrofuran (see Section V.A.4) [184]. A variety of mono- and bifunctional propenyl ethers can readily be prepared by the ruthenium complex-catalyzed isomerization of corresponding allyl ethers [185]. 

Several papers include examples of the strong trans-effect of S-donor ligands in ruthenium(II) complexes. Thus ds-[RuCl2(dmso)4] very quickly gives (23) in... 

Effective disproportionation and co-disproportionation of vinylsilane with ruthenium complexes containing the Ru-H, Ru-Si bond, called subsequently silylative coupling or trans-si y aiion of olefins with vinylsubstituted silanes, was revealed in 1984 as a new synthetic route to substituted vinylsilanes and are commonly used as organic reagents. Subsequent extensive synthetic and catalytic study has shown that silylative coupling of olefins with vinylsubstituted silicon compounds occurs (similarly to the hydrosilylation and dehydrogenative silylation reactions) via active intermediates containing the M-Si (silicometallics) and the M-H bond (where M = Ru, Rh, Ir, Co, Fe). The insertion of olefin into M-Si bond and vinylsilanes into M-H followed by elimination of vinylsilane and ethane respectively, are the key steps in this new process. 

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