Oxidovanadium(IV) Complexes of 3-Hydroxy-4-pyrone and 3-Hydroxy-4-pyridinone Ligands: A New Generation of Homogeneous Catalysts for the Epoxidation of Geraniol

Abstract

A novel generation of homogeneous catalysts for the epoxidation of geraniol, in the presence of tert-butyl hydroperoxide oxidant is reported. Oxidovanadium(IV) complexes of 3-hydroxy-4-pyrone and 3-hydroxy-4-pyridinone ligands exhibit excellent activity and selectivity towards the 2,3-epoxygeraniol product, only differing in the reaction times and turnover frequencies. The pyrone based complexes are the most efficient catalysts showing performances similar to that of the well known oxidovanadium(IV) acetylacetonate catalyst.

Synthesis, characterization and immobilization of a novel mononuclear vanadium (V) complex on modified magnetic nanoparticles as catalyst for epoxidation of allyl alcohols

“…Moreover, due to the relevance to biochemical field and its medicinal applications and as a probe in protein studies, vanadium compounds are used in several industrial fields such as homogeneous and heterogeneous catalysts and battery fabrication . Vanadium complexes including simple vanadium (III, IV, and V) compounds such as VCl 3 , VO(acac) 2 , NaVO 3 as well as vanadium complexes with polydentate ligands such as salophene, 3‐hydroxy‐4‐pyrone and 3‐hydroxy‐ 4‐pyridinone, hydrazones, Schiff bases, tris(pyrazolyl) ethanol, pyrazine‐2‐carboxylate, bishydroxamic acid (BHA) and bis (aryl)‐2‐pyridylmethanol have been used for the homogeneous catalytic oxidation with H 2 O 2 , t‐BuOOH, cumene hydroperoxide (CHP) and O 2 . An application of oxovanadium (IV) compounds as oxidation catalysts was first discovered by Sharpless in the regioselective epoxidation of allylic alcohols .…”

“…An application of oxovanadium (IV) compounds as oxidation catalysts was first discovered by Sharpless in the regioselective epoxidation of allylic alcohols . Vanadium complexes are promising homogeneous catalysts for the epoxidation of allylic alcohols, homoallylic alcohols and alkenes, [18a] oxidative decarboxylation, oxidation of sulfides and oxidation of alkenes, alkanes and aromatic hydrocarbons, Synthesis of epoxide is important because it is widely used in the preparation of natural products and biologically active substances . Moreover, epoxides are also used in synthetic organic chemistry and industrial technology for production of various chemicals including pharmaceuticals and agrochemicals.…”

Catalytic Applications of Vanadium: A Mechanistic Perspective

“…Similarly, in situ generated vanadium carboxylates (phthalate, salicylate, or benzoate) were shown to oxidize anethole to anisaldehyde using H 2 O 2 . Other reports of the epoxidation of alkenes with vanadium complexes containing similar bidentate O,O ligands were also found. − …”

Asymmetric Epoxidation of Chromenes Using Manganese(III) Complexes with Novel Chiral Salen-like Schiff Base Ligands

“…Chiral epoxides are extremely useful building blocks in the synthesis of chiral compounds for the pharmaceuticals as well as for fine chemicals [1][2][3][4]. The use of metal complexes of chiral salen ligands in asymmetric synthesis has been widespread in recent years [5,6].…”