Oxidation of anethole with hydrogen peroxide catalyzed by oxovanadium aromatic carboxylate complexes

Isomerization of Allylbenzenes

“…78−85 Among the microbial approaches, an investigation into the organisms involved in arylpropenoid isomerization and oxidation has resulted in identification of the enzymes able to effectively promote oxidation of the naturally occurring propenylbenzenes. 86−88 Other chemical-based oxidative transformations performed on the substituted phenylpropenoids include epoxidations 89,90 and ozonolytic cleavage. 91 In particular, production of vanillin, an important flavor component, has seen much investigation due to its value, 70,92−94 and the production of "biovanillin" has become a specific focus.…”

“…Because of the increasing demand on these compounds from natural resources, new synthetic approaches to arylpropenoids have become increasingly necessary. In addition, the understanding of the importance of obtaining valuable synthetic compounds from biomass is gaining global momentum. , Examples of natural propenyl compounds being used in other transformations, for instance, the chemical conversion of isosafrole 19 , isoeugenol 18 , and anethole 20 into piperonal, vanillin, and p -anisaldehyde, respectively, have been the focus of intensive research, and recent approaches to these synthetic derivatives include microbial, − electrochemical, and chemical methods. − Among the microbial approaches, an investigation into the organisms involved in arylpropenoid isomerization and oxidation has resulted in identification of the enzymes able to effectively promote oxidation of the naturally occurring propenylbenzenes. − Other chemical-based oxidative transformations performed on the substituted phenylpropenoids include epoxidations , and ozonolytic cleavage . In particular, production of vanillin, an important flavor component, has seen much investigation due to its value, ,− and the production of “biovanillin” has become a specific focus .…”

Catalytic Applications of Vanadium: A Mechanistic Perspective

“…112 Similarly, in situ generated vanadium carboxylates (phthalate, salicylate, or benzoate) were shown to oxidize anethole to anisaldehyde using H 2 O 2 . 113 Other reports of the epoxidation of alkenes with vanadium complexes containing similar bidentate O,O ligands were also found. 114−116 Building off the vanadium-hydroxamic acid (V-HA)catalyzed asymmetric epoxidation of allylic alcohols first reported by Sharpless, 117 Yamamoto developed similar chiral vanadium (as well as Mo, Zr, and Hf) catalysts containing doubly deprotonated C 2 symmetric bishydroxamic acid (BHA) ligands, which exhibited higher activities and stereoselectivities.…”

“…Vanadium­(IV) complexes containing two bidentate O,O-donor ligands (4-acyl-5-pyrazolone) of the formula L 2 VOX, similar to the N,O-donating Schiff base complexes above, were shown to oxidize styrene in the presence of H 2 O 2 (Figure c) . 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. − …”

Photooxidation of Benzene to Phenol by Al2O3-Supported Fe(III)-5-Sulfosalicylic Acid (ssal) Complex

“…With this particular polar medium, the concentration of the hydrophobic hydrocarbon in the aqueous phase is enhanced, and the produced phenols are extracted for the most part in the organic phase. In alcoholwater or acetic acid-water, the catalyst can not exist stably in Fe(III)-ssal form as proved by less phenol yield [15]. Phenol was not obtained in the weak polar acetone [8].…”