Effective oxidation of 1,2-cyclooctene by oxo-vanadium(IV) tetradentate Schiff base complexes under 1 atmosphere of molecular oxygen

Abstract

Development of methods for the understanding of chemical reactivity of high-valent metal-oxo species with respect to organic substrates is important. Here we report a high yield, high TON conversion of cyclooctene using VO (Schiff base) complexes (Figure 1) as catalyst and O 2 as oxidant in MeCN under mild conditions. The results show that catalytic activity increases with a decrease in the number of electron-donating groups. At higher concentration of catalyst and shorter reaction time, a low yield but high selectivity of epoxide was observed.

Synthesis, characterization and catalytic properties of heterogeneous iron(III) tetradentate Schiff base complexes for the aerobic epoxidation of styrene

“…Bell and coworkers have systematically studied the detailed factors controlling activity and selectivity of perhalogenated metal porphyrins as active catalysts for olefin epoxidation from the structural standpoint [13]. Mohebi [14] and Mohebbi [15] also studied the catalytic properties of vanadyl tetradentate Schiff base complexes for aerobic olefin epoxidation based on ancillary ligand modification.…”

Vanadium-Catalyzed Oxidation of Terminal Olefin with Molecular Oxygen: Competing Products between Epoxide and Aldehyde

“…Several vanadium(IV) oxo-based catalyst with salen ligand were previously reported as active catalyst for epoxidation of cyclohexene and cyclooctene with 1 atm of molecular oxygen 25,27,42,43 . However, epoxidations of aliphatic olefin with molecular oxygen catalyzed by such vanadium complexes have not been experimentally and computationally studied.…”

“…We also proposed other possible products, generated from radical isomerizations. In fact, a radical mechanism was recently proposed to proceed in cis-cyclooctene epoxidation, catalyzed by Au cluster 27 .…”

Oxo-bridged bis oxo-vanadium(V) complexes with tridentate Schiff base ligands (VOL)2O (L=SAE, SAMP, SAP): Synthesis, structure and epoxidation catalysis under solvent-free conditions

“…Similar complexes have been used in combination with greener oxidants, i.e. dioxygen, again for cyclooctene epoxidation by THBP, leading to conversion (selectivity) in the range 25-91 % (30-60%) in acetonitrile or in DMF [33,34]. Another [VOL]2 complex containing vanadium(V) atoms and NNO Schiff base ligands has shown good epoxidation activity (94% after 4 h) but in chloroform [35].…”