Access to polysubstituted indoles or benzothiophenes via palladium-catalyzed cross-coupling of furfural tosylhydrazones with 2-iodoanilines or 2-iodothiophenols

Abstract

Palladium-catalyzed cross-coupling of furfural tosylhydrazones with 2-iodoanilines or 2-iodothiophenols produces polysubstituted indoles or benzothiophenes, respectively. The reaction proceeds through 2-furylmethylene palladium iodide intermediates, which undergo furan ring opening followed by ring closure to form indoles or benzothiophenes. This reaction will expand the synthetic applications of furfural derivatives.