Fast Intramolecular Thiol-Activated Arylselenoamides Provide Access to Triggered, Fluorogenic H 2 Se Donors.

H 2 Se is the precursor for the biosynthesis of selenocompounds and is a potential gasotransmitter. Chemical tools for H 2 Se delivery and detection are important for Se-related biology research. Key challenges in the field include developing compound platforms that are triggered to release H 2 Se under various stimuli and developing fluorogenic donors that allow for real-time tracking of H 2 Se delivery. Here we report a new general platform for triggered H 2 Se donors based on controllable deprotection of a thiol, which can quickly activate an intramolecular arylselenoamide ( t 1/2 < 1 min) to release H 2 Se efficiently. Furthermore, we leverage this platform to develop the first examples of fluorogenic H 2 Se donors, which can be used to monitor H 2 Se release by fluorescence in real time. We anticipate that the well-defined donation chemistries will significantly advance the development of H 2 Se donors and stimulate further in-depth studies of H 2 Se biomedicine.