Selective cyclohexene oxidation to allylic compounds over a Cu-triazole framework via homolytic activation of hydrogen peroxide

Abstract

Utilization of metal–organic frameworks as heterogeneous catalysts is crucial owing to their abundant catalytic sites and well-defined porous structures. Highly robust [Cu₃(trz)₃(μ₃-OH)(OH)₂(H₂O)₄]·2H₂O (trz = 1,2,4-triazole) was employed as a catalyst for liquid-phase cyclohexene oxidation with hydrogen peroxide (H₂O₂). Possessing the porous structure together with Lewis acid attributes from the triangular [Cu₃(trz)₃(μ₃-OH)] center, selective oxidation of cyclohexene to allylic products gives a molar yield of 31% with 87% selectivity. According to the highly selective allylic production, the reaction over the present Cu-MOF plausibly occurs via homolytic activation of H₂O₂. This finding elucidates the unique features of the MOF for efficient catalysis of cyclohexene oxidation.