Temperature-Dependent Immobilization of a Tungsten Peroxo Complex That Catalyzes the Hydroxymethoxylation of Olefins

A tungsten peroxo complex stabilized by the bidentate picolinato ligand has been synthesized and then immobilized successfully on imidazole-functionalized silica. The immobilized tungsten-based catalyst was employed as an efficient catalyst for the one-pot synthesis of β-alkoxy alcohols from olefins and methanol with H₂ O₂ . Regarding the catalyst evaluation and the results of characterization by the various methods, it was demonstrated that the immobilization of tungsten peroxo complex was highly temperature-dependent. The tungsten peroxo complex can dissociate and diffuse into the liquid phase at reaction temperature, resulting in a homogeneous reaction. Nevertheless, the catalytically active species was anchored on the imidazole-functionalized silica by hydrogen bonding as the temperature was lowered to 0 °C after the reaction, which thus offered a highly effective approach for recycling the catalyst for consecutive cycles. In addition, various olefins can be converted to the corresponding β-alkoxy alcohols with good conversion and selectivity under relative mild conditions by H₂ O₂ .