Reducing properties of 1,2-dipyridyl-1,2-disodioethanes: chemical validation of theoretical and electrochemical predictions

The reducing properties of highly delocalized radical anions and dianions of 1,2-di(hetero)arylethenes were investigated by theoretical calculations at the PBE0/6-311+G(d,p)/IEFPCM level. The results correlated nicely with the reduction potentials determined by analysis of the voltammetric curves for the reduction of the parent alkenes, and this allowed a reliable scale for their relative reducing strength to be established. In full agreement with calculations and electrochemical results, use of the appropriate 1,2- dipyridyl-1,2-disodioethane as a base led to the successful a-alkylation of bromophenylacetic acids under mild reaction conditions, thus avoiding the competitive reductive cleavage of aromatic C–Br bonds.