Anodic syntheses. Part XV. Further studies with ethylenic acids
Abstract
Contrary to previous reports, βγ-ethylenic acids undergo the Kolbe electrolytic coupling reaction normally, giving a mixture of three products representing the three possible modes of dimerisation of the intermediate allylic radical. The non-terminal double bond in the products retains (ca. 90%) the stereochemistry of the starting materials. With hept-6-enoic acid the intermediate radical undergoes partial cyclisation to the cyclopentylmethyl radical. Electrolysis of terminally unsaturated acids results in some double bond migration unless conditions are used in which the electrolyte does not become alkaline in the course of the reaction.