Reductions at Carbon

Chiral Lewis acid mediated reductions at carbon atom a to a carbonyl group can be carried out either by generation of the radical from o -halo car-... 

A paper has reported that nitrogen-centred radicals (29) have been generated by one-electron reduction (at carbon or metal electrodes) of stable nitrenium ions of the general structure (28). The reactivity of the radicals is influenced by the substituents attached to the two nitrogen atoms that are directly linked to the ion nitrenium centre." ... 

From the two examples studied thus far, it seems that 3,5-epimeri-zation of the 4-keto-intermediate proceeds by stereospecific reduction at carbon-4 to result in formation of a specific deoxysugar. The existence of the 4-keto intermediate is a rational, necessary prerequisite to facilitate these epimerizations via the corresponding enediols. 

Fig. 13.27. Potential vs. current density plots for state-of-the-art fuel cells, o, proton exchange membrane fuel cell , solid oxide fuel cell , pressurized phosphonic acid fuel cell (PAFC) a, direct methanol fuel cell, direct methanol PAFC , alkaline fuel cell. (Reprinted from M. A. Parthasarathy, S. Srinivasan, and A. J. Appleby, Electrode Kinetics of Oxygen Reduction at Carbon-Supported and Un-supported Platinum Microcrystal-lite/Nafion Interfaces, J. Electroanalytical Chem. 339 101-121, copyright 1992, p. 103, Fig. 1, with permission from Elsevier Science.)...

The major reactions of reduction at carbon atoms can be found in Fig. 31.24. Thus, aldehydes and ketones are readily... 

Xu J, Huang WH, McCreery RL. Isotope and surface preparation effects on alkaline dioxygen reduction at carbon electrodes. J Electroanal Chem 1996 410 235-42. 

Bron, M. (2008) Oxygen reduction at carbon black supported gold catalysts. 

P., Fiechter, S., Bron, M., and Tributsch, H. (2006) Oxygen reduction at carbon supported ruthenium-sdenium catalysts selenium as promoter and stabilizer of catalytic activity. J. Power Sources, 155 (1), 47-51. 

Parthasarathy A, S. Srinivasan, A.J. Appleby, C.R. Martin. Eleetrode kinetics of oxygen reduction at carbon-supported and unsupported platinum microcrystallite/Nafion interfaces. J Eleetroanal Chem 1992 339 101-21. 

Fig. 2 Origins of the Piers-Rubinsztajn reaction, (a) reduction of a carbonyl, is followed by, (b) reduction at carbon of the alkoxysilane...

Nogala, W., A. Celebanska, K. Szot, G. Wittstock, and M. Opallo. 2010. Bioelectrocatalytic mediatorless dioxygen reduction at carbon ceramic electrodes modified with bilirubin oxidase. Electrochim. Acta 55 5719-5724. 

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