Promoters ruthenium catalysis

Carborundum, silver on, 27 10-12 3-Carboxy - 2,2,5,5,- tetramethylpyrrolidin-1-oxy m-nitrophenyl ester, enantiomeric specificity in reactions of cyclohexaamy-lose and cycloheptaamylose on, 23 233 Carboxylate ions, 32 117-118 Carboxybc acids a, 3-unsaturated, 25 109 hydrogenation of, 25 107-115 ketonization of, 24 35-37 Lewis base-promoted ruthenium catalysis, 32 389, 400... 

Rhodium (2J) and ruthenium are excellent catalysts for the reduction of aromatic rings. It is with these catalysts that the best chance resides for preservation of other reducible functions (2,10,13,18,41,42,52). Rhodium (41) and ruthenium (45) each reduced methylphenylcarbinol to methylcyclohexyl-carbinol in high yield. Palladium, on the other hand, gives ethylbenzene quantitatively. Water has a powerful promoting effect, which is unique in ruthenium catalysis (36). 

Ionic models for g tensor, 32 11-14 Ionic oxides, see specific oxides Ionic promoters in ruthenium catalysis, 32 387-406... 

The elTiciency of cobalt and ruthenium catalysis is not very sensitive to the presence of promoters )21]. With cobalt, the addition of thorium and alkali promoters increases wax production and supports were incorporated to increase the active metal surface area. On the other hand, promoters and supports are essentia) for iron catalysts. 

It is now usual to promote these cycloadditions by catalysts for example, reaction with A -tosyl-ynamides, using ruthenium or copper catalysts, giving 1-substituted 5- and 4-amino triazoles, respectively the formation of the 1,4-substitution pattern with copper catalysis and 1,5-pattem with ruthenium catalysis seems to be general. The latter metal will also promote addition to internal alkynes. ... 

E3.19 Base-promoted ruthenium carbonyl cluster complexes from fundamental reactions to catalysis... 

Research with an alkali-promoted (potassium or K2O) ruthenium catalyst has demonstrated that ammonia synthesis can be effected at lower temperatures and pressures than those required by the Haber process. As the price of energy increases, ruthenium catalysis might become increasingly important, because the energy-expensive compression process could be avoided. Another advantage of ruthenium if its diminished susceptibility to poisoning by H2O and CO. Ruthenium catalysts can carry out the direct synthesis of ammonia from N2, CO, and H2O ... 

Annual Volume 71 contains 30 checked and edited experimental procedures that illustrate important new synthetic methods or describe the preparation of particularly useful chemicals. This compilation begins with procedures exemplifying three important methods for preparing enantiomerically pure substances by asymmetric catalysis. The preparation of (R)-(-)-METHYL 3-HYDROXYBUTANOATE details the convenient preparation of a BINAP-ruthenium catalyst that is broadly useful for the asymmetric reduction of p-ketoesters. Catalysis of the carbonyl ene reaction by a chiral Lewis acid, in this case a binapthol-derived titanium catalyst, is illustrated in the preparation of METHYL (2R)-2-HYDROXY-4-PHENYL-4-PENTENOATE. The enantiomerically pure diamines, (1 R,2R)-(+)- AND (1S,2S)-(-)-1,2-DIPHENYL-1,2-ETHYLENEDIAMINE, are useful for a variety of asymmetric transformations hydrogenations, Michael additions, osmylations, epoxidations, allylations, aldol condensations and Diels-Alder reactions. Promotion of the Diels-Alder reaction with a diaminoalane derived from the (S,S)-diamine is demonstrated in the synthesis of (1S,endo)-3-(BICYCLO[2.2.1]HEPT-5-EN-2-YLCARBONYL)-2-OXAZOLIDINONE. 

In this paper we disclose the syngas homologation of carboxylic acids via ruthenium homogeneous catalysis. This novel homologation reaction involves treatment of lower MW carboxylic acids with synthesis gas (C0/H2) in the presence of soluble ruthenium species, e.g., Ru02, Ru3(C0)12, H4Ru4(C0)12, coupled with iodide-containing promoters such as HI or an alkyl iodide (1). 

An olefin metathesis/double bond isomerization sequence can be promoted by the catalysis of in situ generated ruthenium hydride species from ruthenium complex 1 (Scheme 41 ).68... 

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