Ultrasound-Assisted Remote Benzylic C(sp3)–H Alkylation of N‑Fluoroamides with Enol Silanes

We have developed an ultrasound-assisted remote benzylic C­(sp3)–H alkylation of N-fluorobenzamides with enol silanes; a series of β-aryl substituted propiophenones was generated in good to high yields. This reaction represents a formal C­(sp3)–C­(sp3) coupling and features simplicity, high efficiency, and wide substrate scope in a multiple-step sequential process, which involves N–F homolysis, 1,5-hydrogen atom transfer, benzylic radical addition, oxidation by copper­(II) salt, and removal of the trimethylsilyl group. Also, DFT theoretical calculations and Marcus theory were employed to consolidate the proposed reaction mechanism.