Selective Oxidation of Olefins Catalyzed by Polymer-anchored Nickel(II) Complex in Water Medium

Abstract

Selective oxidation of olefins has been carried out in water medium with tert-butylhydroperoxide (TBHP, 70% aqueous) as an oxidant using polymer-anchored Ni(II) complex as a catalyst. Several parameters were varied to optimize the reaction conditions. Under the optimized reaction conditions olefins gave selectively allylic oxidation products. The present polymer anchored Ni(II) complex can be recycled five times without any appreciable loss in catalytic activity.

Catalytic Oxidation Processes for the Upgrading of Terpenes: State-of-the-Art and Future Trends

“…This catalytic system was extended to valencene 45, leading to the formation of the corresponding nootkatone 46 with a 60% isolated yield in water, at room temperature (Scheme 17). This result is quite similar to the one obtained with a Cu-Al-Ox catalyst used in acetonitrile at 80 °C [78]. This oxyfunctionalized molecule constitutes an important flavoring constituent due its citrusy, woody, peely, and grapefruitlike aroma profile [91] and is also a natural insect repellent [92].…”

“…In 2014, the team of Guerra developed a novel process for the allylic oxidation of alkenes, catalyzed by a copper-aluminum mixed oxide (Cu-Al Ox), with tert-butylhydroperoxide and a Nickel catalyst. Chloromethylated polystyrene-crosslinked with 2-aminopyridine was used as a macromolecular support for anchoring nickel(II) complex [78]. The obtained catalyst proved to be efficient and reusable for the oxidation of two terpenic olefins (α-pinene 1 and limonene 2) in the presence of t-BHP in aqueous solution with high TurnOver Frequencies (Table 23).…”

“…Table 23. Polymer-anchored nickel(II) complex in allylic oxidation of model terpenes a (adapted from reference [78]). Originally, reeds (Phragmites communis) leaves were used as an eco-respectful template to synthesize cobalt-doped mesoporous silica (Co/SiO2/PC) [77].…”

“…Polymer-anchored nickel(II) complex in allylic oxidation of model terpenes a (adapted from reference[78]). …”

Novel access to verbenone via ruthenium nanoparticles-catalyzed oxidation of α-pinene in neat water

“…-Scheme 1 -Up to now, various catalytic systems, either molecular complexes [16][17][18][19][20] or heterogeneous catalysts [21][22][23][24][25][26][27][28][29][30][31][32], have been used to produce verbenone. Nevertheless, in the most cases, low to medium yields were obtained ( Figure 1) or most of these processes still suffer from various drawbacks, such as sophisticated catalytic systems, toxic organic solvents and high amounts of oxidants, long reaction times, and difficult catalyst's recovery.…”