Cu(ii)-Catalyzed C2-site functionalization of p-aminophenols: an approach for selective cross-dehydrogenative aminations

Abstract

The site selective cross dehydrogenative aminations from precursors without preactivated C-H and N-H bonds has been challenging. Herein, a copper-catalyzed C2-site selective amination of p-aminophenol derivatives with arylamines had been...

Recent Advances in Regioselective C–H Bond Functionalization of Free Phenols

“…Based on controlled experiments, the authors proposed that the amination reaction may undergo a process of radical-radical crosscoupling between the phenoxyl radical 39 and the N-radical 40. In 2022, Zhao et al [24] reported a copper-catalyzed C2-site selective amination of free p-aminophenol derivatives 35 with arylamines 36 under mild conditions, using air as a terminal oxidant, and a variety of C2-site functional aminophenol derivatives 37 were obtained with 39-78% yields (Scheme 7). Interestingly, the para-benzomorpholine substituted phenol was also compatible with the reaction system for transformation into the desired C2-site selective aminated product 37a in 58% yield with oxidation of the benzomorpholine group to 4H-benzo[b] [1,4]oxazine.…”

Catalyst- and additive-free [3 + 3] cyclization–aromatization of β,γ-dioxobutanoate with amines for synthesis ofp-aminophenols

“…2), 11 dyes 12 and photographic materials, 13 and they are often used as precursors for diversification. 14 Because of their versatile structures, the synthesis of p -aminophenols has received considerable attention. However, methods for their synthesis from p -nitrophenols, 15 p -halophenols or p -haloanilines, 16 phenols or anilines 17 suffer from obvious drawbacks, namely multistep synthesis processes, harsh reaction conditions, and the need for expensive catalysts, oxidants and acids.…”