Regioselective Aromatic Perfluoro- tert -butylation Using Perfluoro- tert -butyl Phenyl Sulfone and Arynes.

The selective introduction of perfluoro- tert -butyl group (PFtB, the bulkier analogue of CF 3 group) into arenes has long been sought after but remains a formidable task. We herein report the first general synthetic protocol to realize aromatic perfluoro- tert -butylation. The key to the success is the identification of PFtB phenyl sulfone as a new source of PFtB anion, which reacts with arynes in a highly regioselective manner to afford perfluoro- tert -butylated arenes in high yields. The application of the method is demonstrated by the preparation of sensitive 19 F-labeled NMR probes with an extraordinary resolving ability.