Ruthenium complexes amides

Ruthenium complexes containing this ligand are able to reduce a variety of double bonds with e.e. above 95%. In order to achieve high enantioselectivity, the reactant must show a strong preference for a specific orientation when complexed with the catalyst. This ordinarily requires the presence of a functional group that can coordinate with the metal. The ruthenium-BINAP catalyst has been used successfully with unsaturated amides,23 allylic and homoallylic alcohols,24 and unsaturated carboxylic acids.25... 

The CM of olefins bearing electron-withdrawing functionalities, such as a,/ -unsaturated aldehydes, ketones, amides, and esters, allows for the direct installment of olefin functionality, which can either be retained or utilized as a synthetic handle for further elaboration. The poor nucleophilicity of electron-deficient olefins makes them challenging substrates for olefin CM. As a result, these substrates must generally be paired with more electron-rich crosspartners to proceed. In one of the initial reports in this area, Crowe and Goldberg found that acrylonitrile could participate in CM reactions with various terminal olefins using catalyst 1 (Equation (2))." Acrylonitrile was found not to be active in secondary metathesis isomerization, and no homodimer formation was observed, making it a type III olefin. In addition, as mentioned in Section 11.06.3.2, this reaction represents one of the few examples of Z-selectivity in CM. Subsequent to this report, ruthenium complexes 6 and 7a were also observed to function as competent catalysts for acrylonitrile... 

Ethacrynic acid has been linked to the ruthenium(II)-arene frame via two different approaches. In one approach the acid is connected via an imidazole which coordinates to the ruthenium(II) centre, in place of the pta ligand in RAPTA-type compounds. In the second approach the ethacrynic acid is attached to the arene, via either an amide or ester linker, in such a way that it should be cleaved enzymatically once inside the active site of GST. The ability of the ruthenium complexes to inhibit GST Pl-1 activity was comparable or better than free ethacrynic acid whereas RAPTA-C, employed as a control, exhibited no inhibitory effect on GST Pl-1, even at high concentrations. 

Selective oxidative demethylation of tertiary methyl amines is one of the specific and important functions of cytochrome P-450. Novel cytochrome P-450-type oxidation behavior with tertiary amines has been found in the catalytic systems of low-valent ruthenium complexes with peroxides. These systems exhibit specific reactivity toward oxidations of nitrogen compounds such as amines and amides, differing from that with RUO4. It was discovered in 1988 that low-valent ruthenium complex-catalyzed oxidation of tertiary methylamines 53 with f-BuOOH gives the corresponding a-(f-butyldioxy)alkylamines 54 efficiently (Eq. 3.70) [130]. The hemiaminal type 54 product has a similar structure to a-hydroxymethylamine intermediate derived from the oxidation with cytochrome P-450. 

Three types of product can be obtained from the reaction of amines with carbon monoxide, depending on the catalyst. (1) Both primary and secondary amines react with CO in the presence of various catalysts [e.g., Cu(CN)2, Me3N-H2Se, rhodium or ruthenium complexes] to give V-substituted and V,A-disubstituted formamides, respectively. Primary aromatic amines react with ammonium formate to give the formamide. Tertiary amines react with CO and a palladium catalyst to give an amide. (2) Symmetrically substituted ureas can be prepared by treatment of a primary amine (or ammonia) with CO " in the presence of selenium or... 

In order to facilitate recycling of the multiple TsDPEN-functionalized dendrimer catalysts, the same group recently reported the synthesis of a novel form of hybrid dendrimer ligands by coupling polyether dendrons with peripherally TsDPEN-functionahzed Newkome-type poly(ether-amide) dendrimer (Figure 4.28) [90]. The solubility of these hybrid dendrimers was found to be affected by the generation of the polyether dendron. The ruthenium complexes produced were applied in the asymmetric transfer hydrogenation of ketones, enones, imines and activated... 

PC8HM, Phosphine, dimethylphenyl-, 22 133 iridium complex, 21 97 PC 2H27, Phosphine, tributyl-, chromium complexes, 23 38 PC18H1S, Phosphine, triphenyl-, 21 78 23 38 cobalt complexes, 23 24-25 cobalt, iridium, and rhodium complexes, 22 171, 173, 174 iridium complex, 21 104 palladium complex, 22 169 palladium and platinum complexes, 21 10 ruthenium complex, 21 29 PNOC 2Hl2, Phosphinic amide, diphenyl-, lanthanoid complexes, 23 180 PNAH.2, Propionitrilc, 3,3, 3 -phosphinidy-netri-,... 

Ruthenium complexes of 31, 32 and 33 using the azeotrope triethylamine/formic acid as hydrogen doimor permitted the reduction of P-keto ester, amide and nitrile with high conversion (> 95%) and ee (> 90%) (Scheme 18). The electronic character and the spacer length between the polystyrene part and the benzene ring had very little effect on the reduction outcome, for a same substrate conversion and ee are similar. Here also, it has been shown that the catalyst formed with ligand 32 could be reused at least three times without loss of activity and enantioselectivity. 

More recently, Chatani and his researchers developed the ruthenium-catalyzed carbonylation at the ortho-C-H bonds of aromatic amides [65] to give phthali-mides as their products. Analogously, this reaction can also be transferred to even inactivated C(sp )-H bonds and yield the corresponding succinimides. (Scheme 6.20) [66] In both cases, the presence of 2-pyridinylmethylamino moiety is necessary for these transformations, because it plays an important role as a N,N-bidentate ligand to form a dinuclear ruthenium complex with Ru3(CO)i2. Interestingly, in the absence of ethylene, no carbonylation product could be detected while the efficiency of the reaction decreased in the absence of water. In the latter case, a long reaction time (5 days) is still needed. 

A ruthenium complex (268), formed in situ by [Ru(p-cymene)Cl2] and the amino acid hydroxy-amide ligand (269), catalysed the asymmetric reduction of aryl alkyl ketones to secondary alcohols in moderate to good yields and with up to 97% ee... 

In order to explore the effect of the heteroatom in Fischer-carbene type ligands on the reactivity and thermal stability of ruthenium complexes, Grubbs et al. prepared and characterized a series of well-defined bis-phosphine 4-8, NHC imidazole (IMes) 9-12, and NHC imidazolidine (HglMes) 13 complexes (Figure 12.3) [17]. The exceptionally high stability of 8 at 55 C (20 days before half the complex was decomposed) could be explained by the chelation ofthe amide carbonyl to the ruthenium center. When tested in ROMP reactions, all Fischer carbene complexes demonstrated rapid and quantitative polymerization of norbornene (NBE) derivatives at room temperature, although the polymerization... 

Pioneer examples of ruthenium complexes, which mediate the addion of certain amides to terminal alkynes Heider et al. [185], Kondo et al. [186]. 

Atom-transfer radical cyclization (ATRC) is an atom-economical method for the formation of cyclic compounds, which proceeds under mild conditions and exhibits broad functional group tolerance. Okamura and Onitsuka described a planar-chiral Cp-Ru complex 124-catalyzed asymmetric auto-tandem allylic amidation/ATRC reaction in 2013. This protocol proceeds highly regio, diastereo, and enantioselec-tively to construct optically active y-lactams from readily available substrates in a one-pot manner (Scheme 2.32). In this process, a characteristic redox property of ruthenium complexes would work expediently in different types of catalyzes involving mechanistically distinct allylic substitutions (Ru /Ru ) and atom-transfer radical cyclizations (Ru /Ru ), thus leading to the present asymmetric auto-tandem reaction [48]. 

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