Organic carbonyl compounds

Carbene complexes are isolobal with the corresponding organic carbonyl compounds Hoffmann R (1982) Angew Chem 94 725 Angew Chem Int Ed Engl 21 711... 

Beller and coworkers reported hydrosilylation reactions of organic carbonyl compounds such as ketones and aldehydes catalyzed by Fe(OAc)2 with phosphorus ligands (Scheme 21). In case of aldehydes as starting materials, the Fe(OAc)2/PCy3 with polymethylhydrosiloxane (PMHS) as an H-Si compound produced the corresponding primary alcohols in good to excellent yields under mild conditions [67]. Use of other phosphorus ligands, for instance, PPhs, bis(diphenylphosphino) methane (dppm), and bis(diphenylphosphino)ethane (dppe) decreased the catalytic activity. It should be noted that frans-cinnamaldehyde was converted into the desired alcohol exclusively and 1,4-reduction products were not observed. 

The direct reductive amination (DRA) is a useful method for the synthesis of amino derivatives from carbonyl compounds, amines, and H2. Precious-metal (Ru [130-132], Rh [133-137], Ir [138-142], Pd [143]) catalyzed reactions are well known to date. The first Fe-catalyzed DRA reaction was reported by Bhanage and coworkers in 2008 (Scheme 42) [144]. Although the reaction conditions are not mild (high temperature, moderate H2 pressure), the hydrogenation of imines and/or enam-ines, which are generated by reaction of organic carbonyl compounds with amines, produces various substituted aryl and/or alkyl amines. A dihydrogen or dihydride iron complex was proposed as a reactive intermediate within the catalytic cycle. 

Scheme 42 Direct reductive amination of organic carbonyl compounds...

The reported structural chemistry of zinc aldehyde complexes is dominated by Vahrenkamp and co-workers. A systematic investigation is reported over three papers published in 1999. All X-ray structures reported in these papers are aryl aldehydes and no aliphatic aldehyde structures with zinc were found in the CSD. Zinc is frequently exploited in preparative organic chemistry and enzyme-catalyzed transformations of organic carbonyl compounds. 

Wagner, P. J. Chemistry of Excited Triplet Organic Carbonyl Compounds. 66, 1-52 (1976). 

Only scare data is available in the literature on the application of rhenium containing mono- or bimetallic catalysts in the hydrogenolysis of esters to alcohols. Decades ago Broadbent and co-workers studied the hydrogenation of organic carbonyl compounds (aldehydes, ketones, esters, anhydrides, acids,... 

The blending of polymeric organic carbonyl compounds, e.g., ethylene/carbon monoxide copolymer, with the parent polymer, e.g., polyethylene, gives a plastic film material that degrades within 3 months. 

Photochemically-generated radicals are encountered as reactive intermediates in many important systems, being a major driving force in the photochemistry of ozone in the upper atmosphere (stratosphere) and the polluted lower atmosphere (troposphere). The photochemistry of organic carbonyl compounds is dominated by radical chemistry (Chapter 9). Photoinitiators are used to form radicals used as intermediates in the chain growth and cross-linking of polymers involved in the production of electronic circuitry and in dental treatment. 

Organic carbonyl compounds—aldehydes, ketones, amides, and acyl halides—in which the carbonyl group is not part of a cyclic structure have interesting conformational properties that may differ widely according to the molecular system bearing these substituents. 

CO into a metal-hydrogen bond, apparently analogous to the common insertion of CO into a metal-alkyl bond (6). Step (c) is the reductive elimination of an acyl group and a hydride, observed in catalytic decarbonylation of aldehydes (7,8). Steps (d-f) correspond to catalytic hydrogenation of an organic carbonyl compound to an alcohol that can be achieved by several mononuclear complexes (9JO). Schemes similar to this one have been proposed for the mechanism of CO reduction by heterogeneous catalysts, the latter considered to consist of effectively separate, one-metal atom centers (11,12). As noted earlier, however, this may not be a reasonable model. 

Palladium (II)-Nucleophile Addition across Olefins. Adding palladium complexes to olefins, either in the presence of an external nucleophile or a ligand which is attached to palladium, produces a palladium-carbon sigma-bonded complex which is not usually isolated in the case of monoolefins. Instead it decomposes and in doing so oxidizes the olefin to an organic carbonyl compound or a vinyl compound, exchanges a substituent group on the olefin, isomerizes the double bond, arylates (alkylates) the olefin, or carboxylates the olefin (2, 3). 

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