By ruthenium complexes

Arylamine couplings with ethylene are catalyzed by ruthenium complexes (Equation (103)).97... 

Addition of disulfides to carbon-carbon double bonds is catalyzed by ruthenium complexes (Equation (71)).204 Even relatively less reactive dialkyl disulfides add to norbornene with high stereoselectivity in the presence of a catalytic amount of Cp RuCl(cod). Diphenyl disulfide adds to ethylene and terminal alkenes under identical conditions (Equation (72)). 

Fig. 3.1 G raphical illustration of numbers of reports per year versus date of publication. Data were obtained by searching the Chemical Abstracts Database using the term hydrogenation catalyzed by ruthenium complexes or osmium complexes or rhodium complexes. These are not comprehensive searches but are still representative of the activity in the field.

The concerted delivery of protons from OH and hydride from RuH found in these Shvo systems is related to the proposed mechanism of hydrogenation of ketones (Scheme 7.15) by a series of ruthenium systems that operate by metal-ligand bifunctional catalysis [86]. A series of Ru complexes reported by Noyori, Ohkuma and coworkers exhibit extraordinary reactivity in the enantioselective hydrogenation of ketones. These systems are described in detail in Chapters 20 and 31, and mechanistic issues of these hydrogenations by ruthenium complexes have been reviewed [87]. 

Hydrogen Transfer Reactions Catalyzed by Ruthenium Complexes Linked to P-Cyclodextrin 43... 

Murahashi, S.-I. Komiya, N. Bioinspired oxidations catalyzed by ruthenium complexes, Biomimetic Oxidations Catalyzed by Transition Metal Complexes , Ed. Meunier, B. Imperial College Press London, 2000, pp. 563-611. 

When aldehydes, with or without a hydrogen, are treated with aluminum ethoxide, one molecule is oxidized and another reduced, as in 9-69, but here they are found as the ester. The process is called the Tishchenko reaction. Crossed Tishchenko reactions are also possible. With more strongly basic alkoxides, such as magnesium or sodium alkoxides, aldehydes with an a hydrogen give the aldol reaction. Like 9-69, this reaction has a mechanism that involves hydride transfer.751 The Tishchenko reaction can also be catalyzed752 by ruthenium complexes.753 by boric acid,754 and, for aromatic aldehydes, by disodium tetracarbonylferrate Na2Fe(CO)4,755 OS I, 104. 

Amine Carbonylation Catalyzed by Ruthenium Complexes under Mild Conditions... 

Disproportionation between vinylsilanes and monosubstituted alkenes catalyzed by ruthenium complex (equation 104) has been suggested to occur via a /1-silyl group elimination. The intermediate silylruthenium complex, RuCl(CO)(PPh3)2(SiMe2R1), has been characterized by spectroscopic means194. 

The 1,5-disubstituted 1,2,3-triazole (yvn-triazole) regioisomer may be regioselectively synthesized by using magnesium acetylides1251 or the more recently discovered catalysis by ruthenium complexes.1261 Almost equimolar syn- and antt-triazole mixtures are obtained by heating neat mixtures of the corresponding azides and alkynes at elevated temperatures (Scheme 7.2).[27]... 

Figure 26. Electron-transfer models using Mb. (a) A functionalized prosthetic group linked by ruthenium complex, (b) Electron transfer occurs from the photoexcited ruthenium complex to the hemin and then Ru(III) is reductively quenched by EDTA. (c) Electron transfer occurs from the photoexcited ruthenium complex to Co(III) complex and then one electron is abstracted from the hemin.

A highly regio- and enantio-selective hydroformylation of alkenes, such as PhCH= CH2, CH2=CHCH2CN, and CH2=CHOAc, catalysed by ruthenium complexes with (g) 2,5-disubstituted phospholane ligands has been reported. With (83) as the ligand, the turnover rates over 4000 h-1 at 80 °C, have been attained.108 (Acac)Rh(CO)2-TangPhos [Tangphos = (84)] has been developed as a new enantioselective catalyst for asymmetric hydroformylation of norbornene and other [2.2.1]-bicyclic alkenes (55-92% ee).109... 

For example, the tail-to-tail dimerization of methyl acrylate was catalyzed by ruthenium complexes such as RuHCl(C0)(Pz-Pr3)2/CF3S03Ag or even RuC13 and gave dimethyl hexenedioate isomers. Efficient catalytic systems such as Ru(rf-naphthalene)(COD)/CH3CN, where COD is cyclooctadiene, selectively led to the diester 2 in 75% yield [1] (Eq. 1). 

Reactions Involving Carbonylations Promoted by Ruthenium Complexes... 

Ruthenium catalysts can participate in electron-transfer processes. Thus, a variety of radical reactions of organic halides have been catalyzed by ruthenium complexes, as in the following example [ 126] (Eq. 95). 

Ruthenium is not an effective catalyst in many catalytic reactions however, it is becoming one of the most novel and promising metals with respect to organic synthesis. The recent discovery of C-H bond activation reactions [38] and alkene metathesis reactions [54] catalyzed by ruthenium complexes has had a significant impact on organic chemistry as well as other chemically related fields, such as natural product synthesis, polymer science, and material sciences. Similarly, carbonylation reactions catalyzed by ruthenium complexes have also been extensively developed. Compared with other transition-metal-catalyzed carbonylation reactions, ruthenium complexes are known to catalyze a few carbonylation reactions, such as hydroformylation or the reductive carbonylation of nitro compounds. In the last 10 years, a number of new carbonylation reactions have been discovered, as described in this chapter. We ex-... 

In 1984, the first very effective example of metathesis (disproportionation) of vinylsubstituted silicon compounds catalyzed by ruthenium complexes was reported [33]. It opened a new route of great synthetic importance and has allowed synthesis of a series of unsaturated silicon compounds according to the following equations, with the yield predominantly higher than 70%. Numerous reports on vinylsilane disproportionation (Eq. 21) [5, 33-38] and its co-dis-proportionation with olefins (Eq. 22) [37-44] have been published. 

The molybdenum complex [(CF3)2MeCO]2Mo(NAr)(=CHCMe2Ph) has been observed to be a more efficient catalyst for cyclization of vinyl silyl ether dienes than the ruthenium complex Cl2(PCy3)2Ru(=CHPh), probably because this type of alkene is sterically more demanding (than allyl derivatives) and therefore requires a catalyst less sensitive to steric bulkiness near the reaction center. However, some examples of the RCM of substituted vinylsilanes catalyzed by ruthenium complexes have been reported [127, 131] (Eq. 74). For more examples see Ref. [127]. 

Recently, the use of carbon dioxide as a carbon building block [152] has attracted increasing attention. The hydrosilylation of carbon dioxide catalyzed preferably by ruthenium complexes leads to the synthesis of silyl formate esters (Eq. 98) [153]. Results of the reaction of hydrosilylation in supercritical carbon dioxide as a solvent and substrate have recently been reported [154]. 

Romain S, Vigara L, Llobet A. Oxygen-oxygen bond formation pathways promoted by ruthenium complexes. Acc Chem Res. 2009 42(12) 1944 53. 

Abstract Ruthenium holds a prominent position among the efficient transition metals involved in catalytic processes. Molecular ruthenium catalysts are able to perform unique transformations based on a variety of reaction mechanisms. They arise from easy to make complexes with versatile catalytic properties, and are ideal precursors for the performance of successive chemical transformations and catalytic reactions. This review provides examples of catalytic cascade reactions and sequential transformations initiated by ruthenium precursors present from the outset of the reaction and involving a common mechanism, such as in alkene metathesis, or in which the compound formed during the first step is used as a substrate for the second ruthenium-catalyzed reaction. Multimetallic sequential catalytic transformations promoted by ruthenium complexes first, and then by another metal precursor will also be illustrated. 

Delaney, S., Pascaly, M., Bhattacharya, P.K., etal. (2002) Oxidative damage by ruthenium complexes containing the dipyridophenazine ligand or its derivatives a focus on intercalation. Inorganic Chemistry, 41, 1966-1974. 

In this chapter, the synthesis, structure, and reactivity of several Jt-allylmthenium complexes, and characteristic C-C bond-forming reactions mediated and catalyzed by ruthenium complexes via Jt-allylruthenium intermediates are described. 

The addition of carbonucleophiles to alkynes promoted by ruthenium complexes is not documented. However, several examples of C-H bond addition to alkynes with C-C bond formation have been performed. These involve the ruthenium activation of a C-H bond of aromatic ketones [117, 118] such as 2-methylacetophenone, tetra-lone [119[ (Scheme 8.42), and enones [120, 121]. 

The electrochemical or photochemical reduction of CO2, when catalyzed by ruthenium complexes, also produces formic acid derivatives. Furthermore, ruthenium-catalyzed electrochemical reduction of CO2 can provide carbon-carbon bond-forming reactions. Although at present the efihciency of such electrochemical and photochemical reactions does not appear to be satisfactory for use as a new tool in large-scale organic synthesis, the chemistry suggests that these methodologies may someday be useful in organic synthesis. 

The hydroesterification of allenes with alcohol and CO, when catalyzed by ruthenium complexes, gives acrylates [48, 49]. In the presence of amines, acrylamides are formed in high yields (Eq. 11.17). 

The intramolecular versions catalyzed by ruthenium complexes, and developed independently by the groups of Murai [77] and Mitsudo [78] in 1997, opened the door to the chemistry of noble metal-catalyzed Pauson-Khand reactions (Eq. 11.35). 

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