Li J,
Chen J,
Sang R,
Ham W.-S,
Plutschack MB,
Berger F,
Chabbra S,
Schnegg A,
Genicot C,
Ritter T.
* Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany
Photoredox Catalysis with Aryl Sulfonium Salts Enables Site-Selective Late-Stage Fluorination.
Nat. Chem. 2020;
12: 56-62
Key words
photoredox catalysis - sulfonium salts - fluorination
Significance
The authors report a site-selective late-stage fluorination of aryl sulfonium salts
using photoredox catalysis. This newly introduced leaving group (sulfonium salt) has
a relatively low redox potential and therefore provides easy access to various aryl
radicals. The sulfonium group can be easily attached through thianthrenation of even
complex arenes, which enables a late-stage fluorination of biological active molecules.
Comment
This method was applied to fluorinate over 30 arenes, including 12 drug-like molecules.
Based on detailed experimental studies, Ritter and co-workers propose that the reaction
proceeds through two perfectly meshing catalytic cycles. Therein, the sulfonium leaving
group plays an important part in the recycling of both the iridium and the copper
catalyst.
