Interweaving Visible-Light and Iron Catalysis for Nitrene Formation and Transformation with Dioxazolones

Angew Chem Int Ed Engl. 2021 Jul 19;60(30):16426-16435. doi: 10.1002/anie.202016234. Epub 2021 May 10.

Abstract

Herein, visible-light-driven iron-catalyzed nitrene transfer reactions with dioxazolones for intermolecular C(sp3 )-N, N=S, and N=P bond formation are described. These reactions occur with exogenous-ligand-free process and feature satisfactory to excellent yields (up to 99 %), an ample substrate scope (109 examples) under mild reaction conditions. In contrast to intramolecular C-H amidations strategies, an intermolecular regioselective C-H amidation via visible-light-induced nitrene transfer reactions is devised. Mechanistic studies indicate that the reaction proceeds via a radical pathway. Computational studies show that the decarboxylation of dioxazolone depends on the conversion of ground sextet state dioxazolone-bounding iron species to quartet spin state via visible-light irradiation.

Keywords: dioxazolones; iron catalysis; nitrene transfer; spin state interconverting; visible light.