Amide-Ligand-Promoted Silver-Catalyzed C-H Fluorination via Radical/Polar Crossover
Kenji Yamashita1, Yuki Fujiwara1, Yoshitaka Hamashima1
1School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
Abstract:
We describe an efficient method for benzylic C-H fluorination via sequential hydrogen-atom transfer (HAT) and oxidative radical-polar crossover utilizing the Ag(I)/Selectfluor system. Amide ligands, such as benzamide and sulfonamide, substantially facilitate the processes leading to a carbocation intermediate, which subsequently reacts with nucleophilic fluorinating reagent to form a C-F bond. This protocol is applicable to the fluorination of all 1°, 2°, and 3° C-H bonds as well as to late-stage C-H fluorination of bioactive molecules.
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