ELECTROCHEMICALLY INDUCED CHAIN-REACTIONS - THE ADDITION OF FLUORENE AND INDENE TO AROMATIC-ALDEHYDES INITIATED BY ELECTROCHEMICAL REDUCTION

The electrochemical reduction at -30 degrees C of 2,6-dichlorobenzalde hyde (1a), benzaldehyde (1b), and terephthalaldehyde (2) in tetrahydro furan with tetrabutylammonium perchlorate as supporting electrolyte, u nder an argon atmosphere and in the presence of fluorene or indene, gi ves carbinols resulting from the addition of fluorene or indene and re quires only a catalytic amount of electricity. The chain reaction is i nitiated by proton abstraction from fluorene or indene by a base elect rogenerated by reduction of the aldehyde and the propagation involves the addition of the carbanion to the aldehyde followed by regeneration of the nucleophile by proton transfer from the proton donor to the al koxide anion (base-catalyzed addition). The voltammetric behavior of t he aldehydes in the absence and in the presence of fluorene or indene is also presented.