Reactivity studies of biomimetic catalytic epoxidation of alkenes with tetrabutylammonium periodate in the presence of various manganese porphyrins and nitrogen donors: significant axial ligand π-bonding effects

Metalloporphyrin-Catalyzed Chemoselective Oxidation of Sulfides with Polyvinylpyrrolidone-Supported Hydrogen Peroxide: Simple Catalytic System for Selective Oxidation of Sulfides to Sulfoxides

“…This observation may be due to the involvement of a high-valent Mn-oxo species in the catalytic cycle; ImH as a σ and π electron donor, increases the electron density on the metal centre and facilitates the formation of a high-valent Mn-oxo species. 15 Interestingly, further addition of ImH results in an increased selectivity comparable with that observed in the absence of nitrogen donor. It seems that the increased steric hindrance around the reaction centre caused by the hydrogen bond formation between ImH and methyl phenyl sulfoxide as well as the active oxidant (Fig.…”

“…It seems that the formation of hydrogen bonds between the polymersupported hydrogen peroxide molecules and acetone as the solvent causes the release of H 2 O 2 and the higher reactivity of PVP-H 2 O 2 in acetone relative to the other solvents. It should be noted that the use of protic solvents such as methanol leads to the formation of high valent Mn-oxo species 15,23 and consequently the overoxidation of the sulfoxide to the corresponding sulfone.…”

“…15,16 On the other hand, the oxidizing ability of oxidant depends on the nature of active oxidant involved in the catalytic cycle i.e. the high-valent Mn-oxo species and the six coordinate one, Mn(III)-porphyrin(oxidant)(axial base).…”

Biomimetic Epoxidation of Olefins Catalyzed by Metalloporphyrins with Molecular Oxygen

“…[43][44][45] During the past two decades, the use of metalloporphyrins as catalysts for the epoxidation of olefins has received increasing attention since the leading works of Groves and co-workers by using iodosylbenzene (PhIO) as oxygen atom donor. [46] A variety of oxidants, such as hydrogen peroxides, [47][48][49] iodosylbenzene, [50][51][52] magnesium monoperoxyphthalate, [53][54] tetrabutylammonium monosulfate and eriodate, [55][56] in combination with a large variety of metalloporphyrin catalysts have been employed as oxygen atom donors. For economic and environmental viewpoints, the aerobic epoxidation of olefins catalyzed by metalloporphyrins is attracting more interests.…”

Oxidation of Hydrocarbons with Tetrabutylammonium Oxone Catalyzed by β-Tribrominated meso-Tetraphenylporphyrinatomanganese(III) Acetate in the Presence of N-Bases

“…The biomimetic oxidation of hydrocarbons and nitrogen-and sulfur-containing compounds with different oxygen donors such as PhIO, NaOCl, H 2 O 2 , periodate, amine N-oxides and n Bu 4 NHSO 5 (TBAO) have been extensively studied. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Iron and manganese porphyrins bearing halogen substituents on the periphery of the porphyrin ring have been shown to be particularly efficient for epoxidation and hydroxylation reactions. [21][22][23] Such porphyrins are also more resistant to degradation via free-radical attack or direct oxidation of porphyrin ring than those containing electron-donating substituents.…”