Ruthenium chloride catalyst

Scheme 8.15 Enz5rmatic DKR of alcohols with a pentaphenylcyclopentadienyl ruthenium chloride catalyst.

In an effort directed at developing a racemization catalyst which works uniformly for all the substrates at room temperature, we designed and synthesized a novel aminocyclopentadienyl ruthenium chloride complex 5. The DKR of aromatic as well as aliphatic alcohols could be conducted at room temperature. In case of aromatic alcohols, the substituent effects were found insignificant in the DKR however, aromatic alcohols have comparatively faster conversion rates than their ahphatic counterparts. This is the first ever report of a catalyst... 

Several other versions of these catalysts have been developed. Arene complexes of monotosyl-l,2-diphenylethylenediamine ruthenium chloride give good results with a,(3-ynones.55 The active catalysts are generated by KOH. These catalysts also function by hydrogen transfer, with isopropanol serving as the hydrogen source. Entries 6 to 8 in Scheme 5.3 are examples. 

Hydride ion transfer from formic acid and its salts finds widespread application in the reduction of organic substrates, but limited use has been made of the procedure under phase-transfer catalytic conditions. However in the presence of a ruthenium complex catalyst, it is possible to selectively reduce the C=C bonds of conjugated ketones with sodium formate [11], The rate of reduction is fastest with tetrahexyl-ammonium hydrogensulphate and Aliquat the complete reduction of chalcone being effected within one hour, whereas with benzyltriethylammonium chloride only ca. 15% reduction is observed after two hours under similar conditions. 

In an effort directed at developing a racemization catalyst that works uniformly for a wide range of substrates at room temperature, we designed and synthesized a novel aminocyclopentadienyl ruthenium chloride complex 6 [25]. The DKR of... 

As part of an investigation into new synthetic routes to the important acyclic nucleoside class of antiviral drugs, the cross metathesis of 9-allyl-6-chloropurine with 2,2-dimethyl-4-vinyl-l,3-dioxolane was attempted <2003TL9177>. The reaction was confounded by the coordination of the ruthenium metathesis catalyst with the purine heterocyclic nitrogens. This was overcome to some extent by using the /i-toluenesulfonic acid or hydrogen chloride salts of the... 

Treatment of an aqueous solution of ruthenium chloride and staimous chloride with borohydride gave a precipitate of a ruthenium-tin-boride. The ruthenium is present as the metal and the boron as the boride with electron donation to the ruthenium. The tin exists as a mixture of tin(ll) and tin(IV) oxides which interact with the ruthenium through the oxygens. These catalysts are useful... 

The use of aqueous solutions with basic oxide supports such as magnesium oxide presents some difficulties because of the partial solubility of these oxides in water. To overcome this problem, highly dispersed Ru/MgO catalysts were prepared using ruthenium chloride dissolved in either anhydrous acetone or acetonitrile for the impregnation. ... 

With the ruthenium(I) catalyst [(OC)4Ru2(OAc)2]n (see Section 1.2.1.2.4.2.6.3.1.), cis selectivity was observed in cyclopropanation of trisubstituted alkenes (e.g. 2-methylbut-2-ene, 2,5-dimethylhexa-2,4-diene) with methyl diazoacetate. Furthermore, the interplay between steric, electronic, and lipophilic interactions can occasionally result in enhanced cis selectivity for an individual reaction. Notably, certain homoallyl chlorides were consistently cyclo-propanated by diazoacetates with pronounced cis selectivity in the product cyclopropanes 4 with various catalysts. 

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