Cascade Wolff Rearrangement and Double N‐Acylation: A Cyclization of α‐Diazoketones with 2‐aminopyridines or 3‐aminopyrazoles to Synthesize Fused Pyrimidinediones

A cascade Wolff rearrangement and double N‐acylation reaction has been developed for the synthesis of fused pyrimidinediones in one‐pot under air. These reactions were performed with α‐diazoketones and 2‐aminopyridines or 3‐aminopyrazoles under catalyst‐ and additive‐free conditions. The protocol avoided traditional purification procedures, such as organic solvent extraction and column chromatography. The synthesis of biologically active molecules and gram‐scale experiment demonstrated the potential applications of this reaction.