SYNTHESIS OF BIS(BENZObTHIOPHENYL)METHANES BY GOLD-CATALYZED DOUBLE CARBOTHIOLATION

摘要

Gold-catalyzed double cyclization of bis(2-alkynylphenylthio)acetals (1) produced bis(benzobthiophen-3-yl)methanes (2) in good to excellent yields with high catalyst turnover number. For example, the reaction of (phenyhnethylene)bis((2-(phenylethynyl)phenyl)sulfane) (1b) in the presence of 1 mol of AuCl in toluene at 25 °C for 1 hour gave 3,3'-(phenylmethylene)bis(2-phenylbenzobthiophene) (2b) in 97 isolated yield. The present reaction proceeded through two successive intramolecular carbon-sulfur bond addition reactions, or the so-called carbothiolation.