Tunable ring-opening of 2H-azirines via visible-light-driven novel selective C–C/C–N or CN bond cleavage

Abstract

The visible-light-induced ring-opening of 2H-azirines has primarily focused on the selective cleavage of individual bonds, such as C–C, C–N, or CN. However, simultaneous cleavage of multiple bonds, such as both C–C and C–N, under photochemical conditions has not been reported, and the ability to control distinct ring-opening pathways in a divergent manner remains underexplored. Herein, we report a visible-light-promoted, base-assisted cycloaddition reaction between 2H-azirines and hydrazonyl chlorides via in situ formation of an electron donor–acceptor (EDA) complex. This catalyst-free transformation enables the selective formation of either 1,3,5-triazines or imidazoles, depending on the substitution pattern of the 2H-azirine. Notably, preliminary evaluation of the resulting imidazole derivatives revealed promising optical properties, suggesting potential applications in photonic materials. This work provides a practical and sustainable platform for the construction of diverse nitrogen-containing heterocycles from simple and readily available building blocks.