Anodic Homocoupling of Anions, at-Complexes, Organometallics and Phenolates

2 Anodic Homocoupling of Anions, at-Complexes, Organometallics and Phenolates 

In addition to the carboxylates, other anions can be dimerized at the anode, presumably via radicals. Anionic or enolized 1,3-dicarbonyl compounds and heteroanalogs of CH-acids couple in satisfactory yields (Table 4, entries 1-3). 

With some substrates, the yield is substantially improved with iodide as supporting electrolyte an indirect electrolysis probably takes place here with iodine as electrocatalyst [58]. 

Mediated oxidations with NaBr, Nal of doubly activated methylene compounds CH2XY (X = C02Me, CN, Y = C02Me) can be used to synthesize cyclopropane derivatives [59]. Electrolysis of methylene malonates in the presence of sodium iodide in an undivided cell results in 50-70% yield of stereoisomeric cyclobutane- 

The anodic oxidation of a-sulfonyl carbanions is shown to involve a coupling reaction between the electrogenerated radical and the parent anionic species. The relevance of this mechanism to transition metal oxidations of a-sulfonyl carbanions has been investigated [64]. 

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