Visible-light-driven Cadogan reaction

Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metalfree access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities. (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

A visible-light-driven photochemical Cadogan-type cyclization has been discovered, utilizing the organic D-A type photosensitizer 4CzIPN to efficiently transfer energy and enable access to carbazoles and related heterocycles. Experimental and DFT calculation results demonstrate the robust synthetic capacity and good tolerance of various functionalities in this reaction system.