Electrochemical Generation and Reaction of o-Quinodimethanes from {[[2-(2,2-Dibutyl-2-stannahexyl)phenyl]methyl]thio}benzenes

The anodic oxidation of {[[2-(2,2-dibutyl-2-stannahexyl)phenyl]methyl]thio}benzenes gave o-quinodimethanes which were trapped in situ by dienophiles to give the corresponding cycloadducts in excellent yields. The electron transfer and succeeding 1,4-elimination reaction was efficiently completed in a solution of lithium perchlorate/nitromethane in the presence of acetic acid. The reaction progress was quantitatively controlled by the passage of charge. By using this new method, an aryltetralin lignan skeleton was also synthesized.