Tunable Ring-Opening of 2H-Azirines via Visible-Light-Driven Novel Selective C-C/C-N or C=N 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 C=N. 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 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.