Visible Light Assisted Oxidations of Organic Compounds by Iridium(III)dipyrrinato Complexes

Abstract

Photo-assisted oxidation of organic compounds is a greener and more sustainable approach, which utilizes a very small amount of photocatalyst and visible light or sunlight. Ir(III) cyclometalated complexes have been explored extensively for photocatalytic applications in the past. Alternatively, Ir(III)dipyrrinato complexes can be employed for photocatalysis as they have attractive optical properties with high singlet oxygen generation ability. An efficient protocol for the photocatalytic aerobic oxidations of amines and sulfides by utilizing only 0.05 mol% Ir(III)dipyrrinato complexes is reported. The reactions complete in 2 hours, providing imines and sulfoxides, in excellent yields. Additionally, a methodology for the hydroxylation of aryl boronic acids using 0.05 mol% Ir(III)dipyrrinato catalyst is reported. These methods displayed excellent substrate tolerance and offered an effective strategy for synthesizing a diverse range of functionalized imines, sulfoxides, and phenols in highly efficient manner that validates the versatility of Ir(III)dipyrrinato complexes as photocatalysts for various organic transformations. Notably, these photochemical transformations require only a minimal catalyst loading of 0.05 mol% for these reactions, which demonstrates their exceptional cost-effectiveness.