Reaction of Dilithiated Carboxylic Acids with Iodine: Evidence for the Formation of a Radical Anion Intermediate

Article abstract of DOI:10.1021/jo00251a015

The mechanism for oxidative dimerization of carboxylic acid dianions involves single electron transfer to iodine, producing an organic anion radical.Rearrangement of this species was observed with suitable substrates at a rate competitive with intermolecular reactions.The radical anion can dimerize or react with iodine.The iodide thus generated can be isolated (reaction with excess of iodine) or can participate in a polar S_N2-type reaction sequence leading to dimeric products (reaction with 1/2 equiv of iodine).The interference by free amines (liberated during the metalation with lithium amides) is rationalized by the formation of a charge-transfer complex with iodine which decomposes, liberating protons.