Carbonyl compounds homogeneous catalytic hydrogenation

Homogeneous catalytic transfer-hydrogenation. Sasson and Blum1 introduced the use of this metal catalyst for transfer of hydrogen from primary alcohols to a,/J-unsaturated carbonyl compounds. Thus when benzyl alcohol is heated under nitrogen at 200° for 2 hr. with benzalacetone and the catalyst, benzaldehyde (90% yield) and 4-phenylbutane-2-one (92 % yield) are formed. The reaction can be carried out in a... 

Reduction of nitro compounds to amines is a synthetically important reaction (98) and is practiced since the birth of modern chemical industry—many aromatic amines are key intermediates in production of dyes and pesticides. However, the stoichiometric reductions using iron or alkali metal hydrogen sulfides or catalytic hydrogenations with heterogeneous catalysts leave room for improvements in selectivity, especially with reference to halonitro-derivatives. There are many homogeneous catalysts such as the rhodium carbonyls in the presence of amines or chelating diamines, or [Rus(CO)i2] in basic amine solutions that are... 

Sasson Y, Blum I (1971) Homogenous catalytic transfer-hydrogenation of a, fl-unsaturated carbonyl compounds by dichl(xotris(triphenylphosphine)ruthenium(ll). Tetrahedron Lett 12 2167-2170... 

A metal cluster can be considered as a polynuclear compound which contains at least one metal-metal bond. A better definition of cluster catalysis is a reaction in which at least one site of the cluster molecule is mechanistically necessary. Theoretically, homogeneous clusters should be capable of multiple-site catalysis. Many heterogeneous catalytic reactions require multiple-site catalysis and for these reasons discrete molecular metal clusters are often proposed as models of metal surfaces in the processes of chemisorption and catalysis. The use of carbonyl clusters as catalysts for hydrogenation reactions has been the subject of a number of papers, an important question actually being whether the cluster itself is the species responsible for the hydrogenation. Often the cluster is recovered from the catalytic reaction, or is the only species spectroscopically observed under catalytic conditions. These data have been taken as evidence for cluster catalysis. 

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