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Sequential Vinyl Radical Cyclization/Fixation of Carbon Dioxide through Electrochemical Reduction of Vinyl Bromide in the Presence of an Electron‐Transfer Mediator
Author(s) -
Katayama Asahi,
Senboku Hisanori
Publication year - 2016
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201600508
Subject(s) - chemistry , electrolysis , radical , electrochemistry , vinyl bromide , carbon fixation , cyclic voltammetry , carbon dioxide , bromide , electron transfer , photochemistry , organic chemistry , electrode , electrolyte
Constant‐current electrolysis of vinyl bromide in DMF containing 0.1 m Bu 4 NBF 4 by using an undivided cell equipped with a platinum plate cathode and a magnesium rod anode in the presence of an electron‐transfer mediator, methyl 4‐ tert ‐butylbenzoate, and carbon dioxide resulted in selective generation of a vinyl radical, for which cyclization followed by fixation of carbon dioxide with a carbon–carbon bond formation gave γ,δ‐unsaturated carbo‐ and heterocycle carboxylic acids in moderate to good yields. The vinyl radical could be selectively generated under the electrolysis conditions, and the following reaction of the anion species, generated by one‐electron reduction of the resulting cyclized radical, with carbon dioxide took place efficiently. These results and cyclic voltammetry indicate that methyl 4‐ tert ‐butylbenzoate plays an important role in the generation of vinyl radicals from vinyl bromides. The resulting cyclized γ,δ‐unsaturated carboxylic acid was successfully applied to stepwise and direct iodo‐lactonization to give the corresponding bicycle γ‐lactones in good yields.