One-pot synthesis of diaroyl benzothiepine-1,1-dioxides

Abstract

We report the one-pot two-step synthesis of diaroyl benzothiepine-1,1-dioxides via rongalite-mediated double sulfination of α-bromoacetophenones followed by double condensation of the resulting 1,3-diaroyl sulfones and o-phthalaldehydes. In the (1C + 1C + 1S + 4C) reaction process, a seven-membered ring system could be constructed by two carbon–sulfur (C–S) single bonds and two carbon–carbon double bonds (CC) under mild conditions. A related putative mechanism is proposed and discussed in this article.