Synthesis of Chromeno/Pyrano-quinolines via Tandem Approach involving Michael Addition-Cyclization Catalyzed by L-Proline/Cu(II)

In this study, the reaction of β-nitrovinylquinolines with 1,3-dicarbonyl compounds to furnish chromeno-quinolines under L-proline/Cu(II) catalysis was described. The nitro methyl derivatives of chromeno-quinolines were obtained via the Michael addition followed by the cyclization reaction of cyclic 1,3-dicarbonyl compounds with β-nitrovinylquinolines in a tandem approach. The reaction with open-chain 1,3-dicarbonyl compounds furnished the corresponding aci form of pyranoquinolines.