Transition-metal-free synthesis of polysubstituted pyrrole derivatives via [4 + 1] annulation of β-keto acids (C1 synthon) and α,β-unsaturated imines

Abstract

A novel [4 + 1] annulation protocol for the synthesis of polysubstituted pyrrole derivatives from β-keto acids and α,β-unsaturated imines via a tandem Michael addition, decarboxylation and TBAI-catalyzed oxidative annulation has been developed. This method provides a new and facile application of β-keto acids as 1,1-nucleophilic/electrophilic type C1 synthons.