DBU-promoted cascade selective nucleophilic addition/C–C bond cleavage/hetero-Diels–Alder reactions accompanied by aromatization of substituted 2-amino-4H-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 5H-chromeno­[2,3-b]­pyridin-5-ones. This procedure provides a highly efficient and facile route to functionalized 5H-chromeno­[2,3-b]­pyridines from readily available substrates under mild reaction conditions.

An efficient approach was developed for the synthesis of 4,5‐dihydroisoxazole derivatives from substituted 1,1‐dicyano‐cyclopropanes and hydroxylamine hydrochloride in ethanol through FeCl3‐catalyzed cascade addition reactions. This procedure gives a useful method to afford stereoselectively poly‐substituted 4,5‐dihydroisoxazoles in good yields.

cyclization of cyclopropane-1,1-dicarbonitriles and β-nitrostyrenes was developed to generate highly diastereoselective polysubstituted cyclopent-2-ene-1-carboxamides with good yields. The approach involved cascade ring-opening, cyclization, an amido bond formation from cyano group and adjacent ciscyano/aryl configuration, thus provided a new insight into the donor-acceptor cyclopropane chemistry for the synthesis of complex cyclic compounds.

A formal [3 + 3] cascade annulation strategy for the synthesis of 2-arylchromeno[2,3-b]pyridinones has been developed using 2-aminochromones and substituted cinnamaldehydes or aromatic aldehydes and ethanal as the substrates. The strategy supplies a novel and atom-economical method of accessing a broad range of chromeno[2,3-b]pyridine derivatives in good yields with good functional-group tolerance. The method highlights the inherent practicality of this synthetic transformation.

A pseudo-three-component annulation reaction of substituted 2-amino-4H-chromen-4-ones with aromatic aldehydes promoted by DBU was investigated to access polysubstituted 5H-chromeno­[2,3-b]­pyridines. This reaction included a sequential intermolecular nucleophilic addition/Michael cyclization/intramolecular epoxidation/ring opening/aromatization sequence, which possessed excellent step and atom economy in a single operation for generating 3-hydroxy-5H-chromeno­[2,3-b]­pyridines from readily available substrates.