DBU-Promoted Cascade Selective Nucleophilic Addition/C-C Bond Cleavage/Hetero-Diels-Alder Reactions of 2-Amino-4-chromen-4-ones with β-Nitrostyrenes and/or Aryl Aldehydes: Access to 5-Chromeno[2,3-]pyridin-5-ones.

DBU-promoted cascade selective nucleophilic addition/C-C bond cleavage/hetero-Diels-Alder reactions accompanied by aromatization of substituted 2-amino-4-chromen-4-ones with substituted β-nitrostyrenes or with the combined substituted β-nitrostyrenes and aromatic aldehydes were developed for the synthesis of 2,4-diaryl-substituted 5-chromeno[2,3-]pyridin-5-ones. This procedure provides a highly efficient and facile route to functionalized 5-chromeno[2,3-]pyridines from readily available substrates under mild reaction conditions.