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(VI) Fluoride Exchange (SuFEx) click chemistry and the <i>aza</i>-Ramberg-Bäcklund reaction. This two-step sequence allows the high-yielding 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 arylative strategy relying on a traceless click approach was harnessed in a variety of examples and its mechanism was investigated.