Novel highly selective catalytic oxychlorination of phenols

Abstract

The highly selective oxychlorination of various phenols catalyzed by CuCl2 under mild conditions, in which chloride ions are used as chlorinating agents and dioxygen as a final oxidant, has been developed.

Copper‐Catalyzed Oxybromination and Oxychlorination of Primary Aromatic Amines Using LiBr or LiCl and Molecular Oxygen

“…[27][28][29] However, we observed that non-phenolic compounds were not reactive in these reactions; moreover, phenols having electron-withdrawing substituents also did not react at all. A suggested explanation was a necessary formation of Cu(II) (phenolate) complexes as key intermediates, in which a rate-determining one-electron oxidation of phenolate by Cu(II) to the corresponding phenoxy radicals took place.…”

Aerobic oxychlorination of phenols catalyzed by copper(II) chloride

“…We have recently communicated a remarkable activity of CuCl 2 to catalyze under mild conditions oxychlorination of various phenols with dioxygen affording monochlorinated products [19]. In the present work we report the results of the systematic study of this novel highly chemo-and regioselective reaction.…”

Oxidative Halogenation with “Green” Oxidants: Oxygen and Hydrogen Peroxide

“…The reaction of phenol (1 e) with 2 equivalents of LiCl in the presence of O 2 and 12 mol % CuCl 2 in acetic acid at 80 8C resulted in 93 % conversion and 90 % selectivity towards 4-chlorophenol (173 e; Scheme 61). [177] Analogously, the oxidative bromination of various phenols was performed with LiBr and a catalytic amount of Cu(OAc) 2 ; however, the para regioselectivity was generally lower for bromination than for chlorination. [178] The presence of a hydroxy group on the aromatic nucleus is essential for the reactivity of the aromatic substrate.…”