Example：10.1021/acsami.1c06204 or Chem. Rev., 2007, 107, 2411-2502
Rhodium-Catalyzed [4+2] Annulation of N-Aryl Pyrazolones with Diazo Compounds To Access Pyrazolone-Fused Cinnolines European Journal of Organic Chemistry (IF3.021), Pub Date : 2021-09-17, DOI: 10.1002/ejoc.202101005 Chih-Yu Lin, Wan-Wen Huang, Ying-Ti Huang, Sandip Dhole, Chung-Ming Sun
An efficient synthesis of novel dinitrogen-fused heterocycles, such as pyrazolo[1,2-a]cinnoline derivatives, has been accomplished by the rhodium(III)-catalyzed reaction of N-arylpyrazol-5-ones with diazo compounds. This reaction proceeds through a cascade C−H activation/intramolecular cyclization under mild reaction conditions and features a broad substrate scope.