Rh(III)-Catalyzed Synthesis of Indazolo[2,3-a]quinolines: Vinylene Carbonate as C1 and C2 Building Blocks

A rhodium-catalyzed cyclization of azobenzenes andvinylene carbonate via C-H bond activation to constructindazolo[2,3-a]quinolines has been developed. This protocol offersan efficient method for synthesis of the titled products in goodyields with broad functional group tolerance. In this reaction, threeC-C bonds and C-N bond are formed in one pot, and vinylenecarbonate (VC) acts as C1 and C2 synthons as well asvinylenetransferagent and acylation reagent in the construction of target-fused heterocycles. Moreover, the products exhibit favorablefluorescence properties, which indicate their potential application asfluorescent materials and biosensors.

Automated summary

A rhodium-catalyzed cyclization of azobenzenes and vinylene carbonate has been developed to construct indazolo[2,3-a]quinolines. This method offers high yields and broad functional group tolerance, forming three C-C bonds and one C-N bond in one pot. Additionally, the resulting products exhibit favorable fluorescence properties.