YLIDES GENERATION FROM PHOSPHONIUM AND ARSONIUM SALTS BY ELECTROREDUCTION AND THEIR OXIDATION AND WITTIG REACTION

The products from electroreduction of phosphonium and arsonium salts i n acetonitrile containing supported electrolyte were traced by P-31-NM R spectra and liquid chromatography. (Methoxycarbonylmethyl) triphenyl phosphonium bromide gave the corresponding ylide by hydrogen abstracti on along with triphenylphosphine. Benzyltriphenylphosphonium bromide g ave mainly stilbene as the oxidation products of nonstabilized ylide b esides triphenylphosphine and triphenylphosphine oxide. The correspond ing arsonium salts were reduced and gave mainly triphenylarsine. The e lectroreduction of phosphonium and arsonium salts under the presence o f substituted benzaldehydes gave the olefins from Wittig reactions. Th e ylide formations could be considered as a competitive reactions with the radical cleavage of a substituent on the phosphonium or arsonium salt forming triphenylphosphine and arsine.