6338-19-8Relevant articles and documents
Electrocatalytic Reduction of C-C π-Bonds via a Cobaltocene-Derived Concerted Proton-Electron Transfer Mediator: Fumarate Hydrogenation as a Model Study
Derosa, Joseph,Garrido-Barros, Pablo,Peters, Jonas C.
supporting information, p. 9303 - 9307 (2021/07/19)
Reductive concerted proton-electron transfer (CPET) is poorly developed for the reduction of C-C π-bonds, including for activated alkenes that can succumb to deleterious pathways (e.g., a competing hydrogen evolution reaction or oligomerization) in a standard electrochemical reduction. We demonstrate herein that selective hydrogenation of the C-C π-bond of fumarate esters can be achieved via electrocatalytic CPET (eCPET) using a CPET mediator comprising cobaltocene with a tethered Br?nsted base. High selectivity for electrocatalytic hydrogenation is observed only when the mediator is present. Mechanistic analysis sheds light on two distinct kinetic regimes based on the substrate concentration: low fumarate concentrations operate via rate-limiting CPET followed by an electron-transfer/proton-transfer (ET/PT) step, whereas high concentrations operate via CPET followed by a rate-limiting ET/PT step.
Generation and Reactions of Novel Copper Carbenoids through a Stoichiometric Reaction of Copper Metal with gem-Dichlorides in Dimethyl Sulfoxide
Tezuka, Yasuyuki,Hashimoto, Akio,Ushizaka, Koh,Imai, Kiyokazu
, p. 329 - 333 (2007/10/02)
Copper metal and such gem-dichlorides as α,α-dichloro acid esters, 1a-e, diphenyldichloromethane, 2, benzal chloride, 3, 1,1-dichloro-2-butene, 5, and carbon tetrachloride, 6, were found to produce copper carbenoid intermediates via α,α-elimination of dichlorides along with the formation of CuCl2(DMSO)2.Thus, 1 and 2 gave substituted olefins via a carbenoid coupling reaction.From 5 and 6, reaction products via the oxygen abstraction from DMSO were produced together with dimethyl sulfide; 3 and 4 were found to cause both types of reactions.The carbenoid intermediates formed from 1 did not cause cyclopropanation reaction with cyclohexene in contrast to the conventional carbalkoxy carbenoid generated by a decomposition reaction of ethyl diazoacetate.Also the carbenoid coupling reaction was completely inhibited by the addition of triphenylphosphine, which was contrastive to the formation of phosphonium ylide with a carbenoid from ethyl diazoacetate.
