Iridium-catalyzed [4 + 2] annulation of 1-arylindazolones with α-diazo carbonyl compounds: access to indazolone-fused cinnolines

Abstract

An efficient one-pot Ir-catalyzed method was developed for the synthesis of indazolone-fused cinnolines by [4 + 2] annulation of 1-arylindazolones with α-diazo carbonyl compounds via sequential C–H activation/carbene insertion/cyclization in a tandem manner. This method has excellent tolerance towards electron-withdrawing and electron-donating functional groups on 1-arylindazolone. This method was also found to be applicable to cyclic α-diazo carbonyl compounds.