Photocatalytic Radical Azido/Fluorosulfonylation of Unactivated Alkenes: Accessing Hubs Bridging CuAAC and SuFEx Click Chemistry.

Herein, we describe the successful development of an azido-fluorosulfonylation reaction of alkenes under photoredox catalysis, which could allow the installation of the two "clickable" groups, -N3 and -SO2F, on a C-C double bond, with TMSN3 as the azide source. The utilization of the difunctionalization products is also demonstrated in the construction of a library of 1,2,3-triazolesulfonyl fluoride compounds as well as drug molecule ligation by merging copper-catalyzed azide-alkyne cycloaddition (CuAAC) and sulfur(VI) fluoride exchange (SuFEx), the two generations of click reactions. Mechanistic studies suggest a radical fluorosulfonylation/azidation mechanism and unveil FSO2N3 as a new and potential fluorosulfonyl radical precursor.