Hydrogenation of heteroaromatic compounds

Several heteroaromatic compounds can be hydrogenated by [Rh(COD) (PPh3)2]+ species. Thus, this cationic complex has been reported to be a catalyst precursor for the homogeneous hydrogenation of heteroaromatic compounds such as quinoline [32] or benzothiophene [33]. Detailed mechanistic cycles have been proposed by Sanchez-Delgado and coworkers. The mechanism of hydrogenation of benzothiophene by the cationic rhodium(III) complex, [Rh(C5Me5) (MeCN)3]2+, has been elucidated by Fish and coworkers [34]. 

Basic Isotopic Exchange of Hydrogen of Heteroaromatic Compounds N. N. Zatsepina and I. F. Tupitsyn, Khim. Geterotsikl. Soedin., 1974, 1587-1612. 

The hydrogenation of heteroaromatic compounds can easily be performed at lead cathodes in sulfuric acid electrolytes. Examples are the formation of piperidine or hexahydrocarbazole [17] ... 

The electrochemical hydrogenation of double bonds can be performed either electrocatalytically at Raney nickel, palladium, or platinum modified electrodes [32] or via electron transfer under Birch conditions to the intermediate anion radical [33]. Examples are given in the dihydrogenation of phthalic acid (Eq. 22.15) and the hydrogenation of heteroaromatic compounds (Eq. 22.14). 

Hydrogenation of Heteroaromatic Compounds Pyridines and Related Compounds... 

Recent advances in asymmetric hydrogenation of heteroaromatic compounds (quinoxaline, pyridine, and furan derivatives) 05CJO634. 

Zhou YG (2007) Asymmetric hydrogenation of heteroaromatic compounds. Ace Chem Res 40 1357-1366. doi 10.1021/ar700094b... 

As the asymmetric hydrogenations of amino acid with various kinds of chiral phosphinerhodium complexes as catalysts [68-70], the selective hydrogenations of heteroaromatic compounds [71 ] have been also reported. 

Asymmetric hydrogenation of heteroaromatic compounds provides a straightforward synthetic pathway to access enantioenriched heterocycles, which are of great importance in the synthesis of pharmaceuticals and natural products. Rueping et al. reported several examples of enantioselective cascade transfer hydrogenation reaction of heteroaromatic substrates under metal-free conditions [19,20]. The same group also developed a cascade reaction between enamines 42 and oc,P-unsaturated... 

Wang W-B, Lu S-M, Yang P-Y, Han X-W, Zhou Y-G. Highly enantioselective iridium-catalyzed hydrogenation of heteroaromatic compounds, quinolines. J. Am. Chem. Soc. 2003 125(35) 10536-10537. 

Kuwano R, Sato K, Kurokawa T, Karube D, Ito Y (2000) Catalytic asymmetric hydrogenation of heteroaromatic compounds, indoles. J Am Chem Soc 122 7614-7615... 

Nucleophilic aromatic substitution of hydrogen in heteroaromatic compounds, reactivity and reaction mechanisms 94MI2. 

The Brpnsted acid catalyzed hydrogenation of quinolines with Hantzsch dihydropyridine as reducing agent provides a direct access to a variety of substituted tetrahydroquinolines (Table 4.2). The mild reaction conditions of this metal-free reduction of heteroaromatic compounds, high yields, operational simplicity and practicability, broad scope, functional group tolerance and remarkably low catalyst loading render this environment-friendly process an attractive approach to optically active tetrahydroquinolines and their derivatives (Table 4.3) (see page 176). ... 

Hydrogen Exchange of Heteroaromatic Compounds Y. Kawazoe and M. Maeda, Kagaku no Ryoiki, Zokan, 1970, 92, 39-96. 

Homolytic substitution of heteroaromatic compounds, 16, 123 Hydantoins, chemistry of, 38, 177 Hydrogen cyanide derivatives, synthesis of heterocycles from, 41, 1 Hydrogen exchange base-catalyzed, 16, 1 one-step (labeling) methods, 15, 137 Hydrogenated porphyrin derivatives hydroporphyrins, 43, 73 Hydroxamic acids, cyclic, 10, 199 1 -Hydroxyindoles, 1 -hydroxytryptophans, and 1-hydroxytryptamines,... 

---