Base and Nucleophilic Catalysis Enables Formal [3+2] Cycloaddition of Alkynyl Diazoketones and Aminomalonates: Access to γ,γ‐Disubstituted 3‐Pyrrolin‐2‐ones

ABSTRACT A formal [3+2] cycloaddition of alkynyl diazoketones with aminomalonates has been developed, providing rapid access to highly substituted γ,γ‐disubstituted 3‐pyrrolin‐2‐ones. This transformation proceeds under mild conditions with broad substrate scope and good functional‐group tolerance, providing a practical approach to synthetically valuable five‐membered nitrogen heterocycles. Furthermore, the reaction can be readily performed on gram scale, and the obtained products undergo versatile downstream transformations, demonstrating the synthetic utility of this methodology.