Harnessing Sulfur(VI) Fluoride Exchange Click Chemistry and Photocatalysis for Deaminative Benzylic Arylation

Abstract

While among the most common functional handles present in organic molecules, amines are a widely underutilized linchpin for C–C bond formation. To facilitate C–N bond cleavage, large activating groups are typically used but result in the generation of stoichiometric amounts of organic waste. Herein, we report an atom-economic activation of benzylic primary amines relying on the Sulfur Fluoride Exchange (SuFEx) click chemistry and the aza-Ramberg-Bäcklund reaction. This two-step sequence allows the efficient generation of 1,2-dialkyldiazenes from primary amines via loss of SO2. Excitation of the diazenes with blue light and an Ir photocatalyst affords radical pairs upon expulsion of N2, which can be coaxed into the formation of C(sp3)–C(sp2) bonds upon diffusion and capture by a Ni catalyst. This unique arylative strategy relying on a trace-less click approach was harnessed in a variety of examples and its mechanism was investigated.

Cross-Coupling of Amines via Photocatalytic Denitrogenation of In Situ Generated Diazenes

“…Thus, there remains a strong interest in the development of amine cross-coupling reactions that are simple, versatile, and broadly tolerant of various functional groups for the direct generation of new C­(sp 3 )–C­(sp 3 ) coupled products. Here, we report such a method involving the photocatalytic denitrogenation of in situ-generated diazenes …”