Photochemical Reaction Discovery Enabled by the Dynamic Speciation of Copper Complexes.

Rapid access to molecules with tailored function is essential to advancing the discovery of new medicines, materials, and agrochemicals. Chemical reaction discovery enables it by expanding access to underexplored chemical space and providing more strategies for constructing molecular targets. Among new technologies, photochemical transformations have been revived as a valuable platform for uncovering new reactivity, especially when combined with accelerated reaction discovery platforms. Herein, we report a strategy for accelerated photochemical reaction discovery based on the dynamic speciation of copper complexes, enabled by their metal-ligand bond lability. This approach simplifies reaction screening by employing an earth-abundant copper(II) salt and commercially available ligands to reversibly generate multiple catalytic species in situ, thereby obviating the need for well-defined complexes or photocatalysts. The workflow engaged ubiquitous functional groups in multiple transformations. Specifically, amines and carboxylic acids were employed in deaminative and decarboxylative alkyl azidation of alkenes, enabling the modification of amino acids, peptides, and complex molecules. These products can be further derivatized in one pot through click reactions or by a modular heteroannulation strategy.