Amidative β-Scission of Alcohols Enabled by Dual Catalysis of Photoredox Proton-Coupled Electron Transfer and Inner-Sphere Ni-Nitrenoid Transfer
Hyeyun Keum, Harin Ryoo, Dongwook Kim, Sukbok Chang
Abstract
The photoredox/Ni dual catalysis is an appealing strategy to enable unconventional C–heteroatom bond formation. While significant advances have been achieved using this system, intermolecular C(sp 3 )–N bond formation has been relatively underdeveloped due to the difficulty in C(sp 3 )–N reductive elimination. Herein, we present a new mechanistic approach that utilizes dioxazolones as the Ni(II)-nitrenoid precursor to capture carbon-centered radicals by merging proton-coupled electron transfer (PCET) with nickel catalysis, thus forming synthetically versatile N -alkyl amides using alcohols. Based on mechanistic investigations, the involvement of (κ 2 - N, O )Ni(II)-nitrenoid species was proposed to capture photoredox PCET-induced alkyl radicals, thereby playing a pivotal role to enable the C(sp 3 )–N bond formation.