Synthesis of disulfides tethered pyrroles from β-ketothioamides via a bicyclization/ring-opening/oxidative coupling reaction.

A DABCO-promoted three-component reaction of β-ketothioamides (KTAs), arylglyoxals and 2-cyanoacetates to construct disulfides tethered pyrroles by using air as an oxidant has been disclosed. Importantly, this protocol involves a tandem sequence that includes Knoevenagel condensation, Michael addition, N-cyclization, O-cyclization, ring-opening and oxidative coupling.