Synthesis of Fused-Ring Pyrrolizine Derivatives via a Copper-Catalyzed Radical Cascade Cyclization

Herein, an atom-economic method for the synthesis of fused-ring pyrrolizine derivatives by a cycloaddition reaction of easily accessible N-substituted pyrrole-2-carboxaldehydes with N-substituted maleimides in the presence of di-tert-butyl peroxide has been successfully developed. A total of 23 compounds were obtained by using this method, with a maximum yield of 72%, providing a practical and efficient method for the synthesis of tricyclic pyrrolizine frameworks.