Energy Transfer-Enabled Unsymmetrical Diamination Using Unprecedented Bifunctional Nitrogen-Radical Precursors

Vicinal diamines, especially unsymmetrical ones, are among the most common structural motifs in biologically active molecules, natural products, and pharmaceuticals. While the catalytic diamination of carbon–carbon double bonds provides rapid access to diamines, these reactions are often limited to installing undifferentiated amino functionalities through transition-metals or hyper-valent iodine reagents catalysis. Herein, we disclose a metal-free, photosensitized dearomative unsymmetrical diamination of various electron-rich (hetero)arenes with bifunctional diamination reagents, producing a series of previously inaccessible vicinal diamines with excellent regio- and diastereoselectivity. A class of unprecedented bifunctional nitrogen-radical precursors was developed for the first time to simultaneously generate two N-centered radicals with different reactivities via an energy transfer (EnT) process. In addition, the protocol was also suitable for a wide range of alkenes. Notably, the formed vicinal diamines bear two differentiated amino functionalities, and either imine or amide units could be easily and orthogonally convertedconverted converted converted into unprotected amines, thereby facilitating the selective downstream transformations.