Radicals as Exceptional Electron-Withdrawing Groups: Nucleophilic Aromatic Substitution of Halophenols Via Homolysis-Enabled Electronic Activation.

ABSTRACT: While heteroatom-centered radicals are understood to be highly electrophilic, their ability to serve as transient electron-withdrawing groups and facilitate polar reactions at distal sites has not been extensively developed. Here, we report a new strategy for the electronic activation of halophenols, wherein generation of a phenoxyl radical via formal homolysis of the aryl O-H bond enables direct nucleophilic aromatic substitution of the halide with carboxylate nucleophiles under mild conditions. Pulse radiolysis and transient absorption studies reveal that the neutral oxygen radical (O^•) is indeed an extraordinarily strong electron-withdrawing group [σ_p^-(O^•) = 2.79 vs σ_p^-(NO₂) = 1.27]. Additional mechanistic and

SUBMITTER: Shin NY 

PROVIDER: S-EPMC10512454 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature