Complex CpRu

The reaction of 4-difluorophosphino-[l,2,3]diazaphosphole 115, even in an excess amount, with CpRu(PPh3)2Cl resulted in the formation of monosubstituted complex CpRu(PPh3)(115)Cl only (Scheme 35). In contrast to the monosubstitution... 

Ruthenium catalysts have also been used in this context.200,201 In particular, the cationic ruthenium complex, CpRu(CH3CN)3PF6, in conjunction with carboxylic acid ligand 3, has been used to achieve the remarkably chemoselective allylation of a variety of alcohols via dehydrative condensation with allyl alcohol (Equation (50)).202 It is worth noting that this transformation proceeds with 0.05 mol% catalyst loading and does not require the use of excess allyl alcohol. 

When the initial hydride CpRuH(CO)(PH3), It, is placed near H3O+, a proton transfer occurs without the energy barrier to form the dihydrogen complex [CpRu(H2)(CO)(PH3)]+, in good agreement with the data of Orlova and Scheiner [42]. Dihydrogen-bonded intermediates appear on the protonation pathway if the hydride It interacts with the weaker acids TFA and PFTB. However, the... 

In the isoelectionic ruthenium series, nucleophilic substitution by the disodium salt of 4,4 -dihydroxy-benzophenone on the complex (32) of p-dichlorobenzene with a [RuCp]+ unit produced the aromatic polyether complex represented by (33). Displacement by DMSO at 160 C led to the free polymer and the recoverable complex [CpRu(DMSO)3]+, which can be recycled directly by complexation with p-dichlorobenzene (equation 26). While ruthenium is not attractive to use in stoichiometric processes, this example appears to allow easy recycling.80... 

Using the complex CpRu(CH3CN)3PF6 as a catalyst, reaction can proceed at room temperature in dimethylformamide (DMF) [36] (Eq. 25). 

Ruthenacyclopentenes have also been proposed as intermediates in the intramolecular coupling reaction of the C=C bond and the C=C bond. Thus, the complex CpRu(CH3CN)3PF6 catalyzed the cycloisomerization of a variety of... 

The catalytic activation of allylic carbonates for the alkylation of soft car-bonucleophiles was first carried out with ruthenium hydride catalysts such as RuH2(PPh3)4 [108] and Ru(COD)(COT) [109]. The efficiency of the cyclopen-tadienyl ruthenium complexes CpRu(COD)Cl [110] and Cp Ru(amidinate) [111] was recently shown. An important catalyst, [Ru(MeCN)3Cp ]PF6, was revealed to favor the nucleophilic substitution of optically active allycarbonates at the most substituted allyl carbon atom and the reaction took place with retention of configuration [112] (Eq. 85). The introduction of an optically pure chelating cyclopentadienylphosphine ligand with planar chirality leads to the creation of the new C-C bond with very high enantioselectivity from symmetrical carbonates and sodiomalonates [113]. 

The cationic ruthenium complex [CpRu(MeCN)3]+(PF6) catalyses the hydro-silylation of alkyne with triethylsilane in good yield and with very limited formation of Unear 1,2-disubstituted products (Eq. 17, Table 4). 

In addition to these intramolecular [2+2+2] cycloadditions, intramolecular [4+2] cycloaddition of yne-enones 29 leading to fused pyrans 30 has been achieved by means of the ruthenium catalysis with a cationic complex, CpRu(MeCN)3PF6 (Eq. 15) [24], Such hetero Diels-Alder cycloaddition was considered to proceed via an oxaruthenacycle 31. 

The main methodologies developed until now for enantioselective oxidation of sulfides are effective only in the oxidation of alkyl aryl sulfoxides. Dialkyl sulfoxides on the other hand are generally oxidized with only poor selectivity. In an attempt to solve this problem, Schenk s group69 recently reported a stereoselective oxidation of metal-coordinated thioethers with DMD. The prochiral thioether is first coordinated to a chiral ruthenium complex by reaction with the chloride complexes [CpRu[(S,S)-chiraphos]Cl], 36. Diastereoselective oxygen transfer from DMD produces the corresponding sulfoxides in high yield and selectivity. The chiral sulfoxides 37 are liberated from the complexes by treatment with sodium iodide. Several o.p. aryl methyl sulfoxides have been obtained by this method in moderate to high ee (Scheme 12). 

The expected cr-vinyl complex > -CpRu(PPh3)2[(Me02C)C=C(C02Me)H] is obtained, among other products, in the reaction of / -CpRuH(PPh3)(CO) with... 

Photolytic cleavage of the benzene-Ru bond of 105 in acetonitrile gives a quantitative yield of the pale orange, crystalline complex [CpRu(CH3CN)3] [PFg] (106). The acetonitrile ligands in 106 are labile and the compound therefore serves as a convenient transfer agent for the CpRu" fragment. A selection of (arene)RuCp complexes made by this route is assembled in Scheme 11. 

Studies of nucleophilic attack on the 7r-bound benzo[b]thiophene (BT) complexes [CpRu(BT)] and [Cp Ir(BT)] have been undertaken as potential models for the reactions of BT on hydrodesulfurization (HDS) catalysts. In these complexes, the BT coordinates to the metal via the benzene rather than the thiophene ring. A range of nucleophiles, including hydrides and sulfides which are proposed to be present on HDS catalyst surfaces, add to the benzene ring to give primarily C-7 adducts see Eq. (24). However, products that might be precursors to, or are similar to, proposed intermediates in the HDS of BT, such as... 

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