C−F Transformations of Benzotrifluorides by the Activation of Ortho‐Hydrosilyl Group

Single C−F transformations of aromatic trifluoromethyl compounds are challenging issues due to the strong C−F bond. We have recently developed selective methods for single C−F transformations such as allylation of o‐hydrosilyl‐substituted benzotrifluorides through the hydride abstraction with trityl cations. Single C−F thiolation and azidation of o‐(hydrosilyl)benzotrifluorides were achieved using trityl sulfides and trityl azide catalyzed by Yb(OTf)3. Treatment of o‐(hydrosilyl)benzotrifluorides with trityl chloride resulted in single C−F chlorination. The resulting fluorosilyl group served in further transformations including protonation, halogenation, and Hiyama cross‐coupling with C−Si cleavage. We also synthesized benzyl fluorides by LiAlH4‐reduction of the resulting fluorosilanes and further C−F transformations. These methods enabled us to prepare a broad range of organofluorines from simple benzotrifluorides through C−F and C−Si transformations.