Visible-Light-Promoted α-C(sp3)-H Amidation of Cyclic Ethers under Redox-Neutral Conditions.

Reported herein is a visible-light-promoted strategy for the α-C(sp3)-H amidation of cyclic ethers using N-acyloxyamide as an oxidative amidating reagent. This transformation provides a straightforward approach to various α-amidated cyclic ethers under metal- and additive-free conditions. The synthetic utility of the products was demonstrated through facile transformations, including reduction, allylation, acylation, sulfonamidation, and gram-scale reactions. Preliminary mechanistic studies suggest a radical/radical cross-coupling process, with C(sp3)-H bond cleavage identified as the rate-determining step.