Synthesis, Structure, and Reactivity of [Cu(phen)2]ClO2: Aerobic Oxidation of Cl- to ClO2- at Room Temperature

An unusual 4e– oxidation of Cl– into ClO2– occurred during the reaction between CuCl and phenanthroline (phen) in air to form a [Cu(phen)2]ClO2 complex, which is capable of oxidizing catechol into the highly substituted pentenone derivative methyl 1‐hydroxy‐2‐oxo‐4,5,5‐trimethoxycyclopent‐3‐ene‐1‐carboxylate through contraction of the aromatic ring by extradiol C–C bond cleavage concomitant with the further formation of a C–C bond. The copper(II)‐catalyzed aerobic oxidation of Cl– to ClO2– to form the [Cu(phen)2]ClO2 (phen = phenanthroline) complex at room temperature is reported. The oxidation of catechol by using [Cu(phen)2]ClO2 yields methyl 1‐hydroxy‐2‐oxo‐4,5,5‐trimethoxycyclopent‐3‐ene‐1‐carboxylate including 4,5‐dimethoxy‐1,2‐benzoquinone