Selective Reduction of the CarbonBromine Bond in Bromo Epoxides

Abstract: A mild, selective, and efficient method for the Pd-catalyzed reduction of aryl bromides and iodides by hypercoordinate polymethylhydrosiloxane (PMHS) is reported. In contrast to related methods, the hydrodehalogenations described herein are amine free and can be carried out in THF with relatively low loads of catalyst. Furthermore, we have evidence to suggest that the reduction of bromostyrene proceeds differently than previously described.

Abstract: Several vinyl halides previously used in inositol syntheses were subjected to electrochemical reduction. The unreactivity of allylic alcohols or allylic ethers at the applied potentials allowed the...

Abstract: The influence of various parameters including solvent, base and temperature on the reaction between carbazole and epoxides was studied. This led to the development of a regioselective ring-opening ...

Abstract: Reduction Cyclic Alkanes Arenes Alkenes Alkynes Organic Halides Amines and Derivatives Nitro Compounds Ethers Alcohols and Phenols Sulfur Compounds Selenium and Tellurium Compounds Aldehydes and Ketones Acetals Carboxylic Acids Acid Halides Anhydrides Esters and Lactones Nitriles Isonitriles Keywords: alkanes; arenes; cycloalkanes; reduction; decarbonylation; dehalogenation; deamination; desulfuration; hydrogenation catalysts; chiral ligands; metal hydrides

Abstract: Polarographic and cyclic voltammetric studies of bromohydrins in acetonitrile showed a single diffusion-limited two-electron irreversible cathodic wave/peak followed by chemical transformations Controlled-potential electrolyses of the compounds gave a mixture of two products with epoxide as one of them in all cases The mechanism of reduction is discussed in the light of proton-transfer reactions in neutral aprotic media

Abstract: The anodic oxidation of aliphatic sulfides has been investigated, using cyclic voltammetry and controlled potential electrolysis. Reactions of dimethyl sulfide in acetonitrile have been studied in detail, considering the effects of variation of water content and of type of supporting electrolyte. With as much as 1% water in , dimethyl sulfide is completely oxidized to dimethyl sulfone. In anhydrous , the products are and . It is suggested that the electrochemical reaction involves formation of protons and , which condenses with to form . When perchlorate is present as supporting electrolyte, it is involved in a slow chemical reaction which produces Cl−, , and . The reaction of benzyl methyl sulfide is very similar, leading to benzaldehyde and .

Abstract: A novel access to β-hydroxy carbonyl compounds from the corresponding α,β-epoxy carbonyl compounds has been attained through the recyclable use of diphenyl diselenide or diphenyl ditelluride as an electroreduction mediator in a MeOH-NaClO 4 -(Pt) system α,β-Epoxy ketones are converted to the corresponding aldols in the presence of malonic esters Similarly, α,β-epoxy esters and nitriles can be reduced to the corresponding β-hydroxy compounds in the presence of acetic acid

Abstract: The electrochemical behaviour of the epoxides having the structure with R being an aromatic ring (or any unsaturated system) is described in the couple: DMF-tetraalkylammonium salts on a mercury cathode. The opening of the ring corresponds to a two-electron mechanism but further cleavages of C—O bonds are observable. Indirect reduction of the epoxide by means of an electrogenerated anion-radical or/and dianion of some well chosen mediators is also possible. In some cases, the redox catalysis can also be autocatalysed when the opening is followed by an elimination with production of an unsaturated hydrocarbon which is able to lead rapidly to a stable anion-radical which then plays the rǒle of reducing of the starting material in homogeneous phase.