Red emitting heteroleptic Ir(III)-complexes: competent photocatalysts for chemoselective ring expansion of indoles.

4-Quinolones and tryptanthrin are active pharmaceuticals, with great demand due to their biological activities. Phosphorescent Ir(III)-dipyrrinato complexes are synthesized and employed as photocatalysts for one-step conversion of indoles to 4-quinolones and tryptanthrin, respectively, in high yields. The method is versatile; it utilizes just 1 mol% of Ir-catalyst under oxygen and blue light, much lower than the previously reported catalysts for quinolone synthesis.