Metal‐Free Modular S–N/O–N Bond Construction through Photolyzed Nitrenes

Comprehensive Summary Nitrene‐mediated S–H/O–H insertion reactions serve as a core strategy for constructing value‐added N–S/N–O bonds, which are indispensable motifs in pharmaceuticals, functional materials, and agrochemicals. However, traditional approaches are plagued by intractable issues: severe side reactions ( e.g ., Curtius rearrangement), harsh reaction conditions, and transition‐metal catalyst deactivation caused by strong coordination of thiols/alcohols. Herein, we report a metal‐free photochemical protocol using dibenzothiophene sulfilimines as nitrene precursors, triggered by 365 nm LED irradiation at room temperature. Simple additives (2‐amino‐4‐chlorobenzoic acid) play dual pivotal roles: mediating triplet energy transfer to activate sulfilimines and acting as proton donors to suppress side reactions. Comprehensive mechanistic studies (radical capture experiment, EPR, nanosecond transient absorption spectroscopy, and DFT calculations) confirm singlet nitrene as the key reactive intermediate for the dominant pathway, while a triplet nitrene‐mediated radical‐radical cross‐coupling mechanism is also feasible for thiol substrates. This protocol features broad substrate compatibility, scalable synthesis without yield loss, and validated synthetic utility, providing a practical avenue for efficient N–S/N–O bond formation.