We report an efficient tandem 4 + 1 annulation method for synthesizing functionalized spiro bis‐ γ ‐lactams from chromone‐2‐carboxamides and maleimides. These spiro compounds integrate chromone, pyrrolidone, and unique spirocyclic skeletons in one molecular framework, endowing them with diverse structural characteristics. Moreover, the chromone ring‐opening reaction of these products provides access to another class of spiro bis‐ γ ‐lactams bearing multiple substituents. This approach enables the efficient construction of a diverse library of potentially bioactive spiro bis‐γ‐lactam derivatives and serves as a valuable platform for related synthetic studies.
Chen et al. (Fri,) studied this question.