Ultrasound-Assisted\nRemote Benzylic C(sp<sup>3</sup>)–H Alkylation of <i>N</i>‑Fluoroamides with\nEnol Silanes

We\nhave developed an ultrasound-assisted remote benzylic\nC(sp<sup>3</sup>)–H alkylation of <i>N</i>-fluorobenzamides\nwith enol silanes; a series of β-aryl substituted propiophenones\nwas generated in good to high yields. This reaction represents a <i>formal</i> C(sp<sup>3</sup>)–C(sp<sup>3</sup>) coupling\nand features simplicity, high efficiency, and wide substrate scope\nin a multiple-step sequential process, which involves N–F homolysis,\n1,5-hydrogen atom transfer, benzylic radical addition, oxidation by\ncopper(II) salt, and removal of the trimethylsilyl group. Also, DFT\ntheoretical calculations and Marcus theory were employed to consolidate\nthe proposed reaction mechanism.