One-pot construction of pyrazolo[5,1-a]isoindoles via t-butyl carbazate-mediated double Michael addition/cyclocondensation of diaroyl benzothiepine-1,1-dioxides.

This article reports one-pot synthesis of aroylmethyl-conjugated pyrazolo[5,1-a]isoindoles via t-butyl carbazate-mediated double Michael addition/cyclocondensation of diaroyl benzothiepine-1,1-dioxides. In the reaction process, the seven-membered ring is converted into a bicyclo[5.5] core skeleton by the formation of two carbon-nitrogen single bonds and one carbon-nitrogen double bond under mild conditions. The related plausible mechanism is also discussed here.