Mechanism of oxidation of aryl methyl sulfoxides with sodium hypochlorite catalyzed by (salen)MnIII complexes

Mechanism of (Salen)manganese(III)‐Catalyzed Oxidation of Aryl Phenyl Sulfides with Sodium Hypochlorite

“…This demonstrates that PyO is not binding with the oxo(salen)manganese(V) complex and has no catalytic effect during the oxidation process. Similar results have been obtained in the epoxidation of olefins [7] and in the oxidation of aryl methyl sulfides [20] [34], aryl phenyl sulfides [21], sulfoxides [33] [36], and arylthioacetic acids [40] by oxo(salen)manganese(V) complexes. The observed result is consistent with the observation that the porphyrinatomanganese complexes lack affinity for the sixth axial ligand [41].…”

“…e ) The 1 values were obtained by correlating log k 2 with s p for the reaction of various sulfides with a given oxo(salen)manganese( V ) complex. Table 1 show that the presence of Me or Ph groups at the 7,7'-positions slightly reduces the rate as in the case of aryl methyl sulfides [20] [34], sulfoxides [33] [36], and arylthioacetic acids [40]. The oxo(salen)manganese(V) oxidation of 4-substituted phenyl phenyl sulfides was also carried out at four different temperatures (see Table 5).…”

“…With the aim of establishing the optimum conditions for the synthesis of sulfoxides and sulfones and the mechanism of oxometal ion oxidation of organic sufides, we have studied extensively the kinetics and mechanism of oxo(salen)metal ion oxidation of organic sulfur compounds [20] [21] [27] [30 -33]. Recently, we have reported the results on the [Mn III (salen)]-catalyzed NaOCl oxidation of aryl methyl sulfides [34] [35] and sulfoxides [36]. A diphenyl sulfide may behave differently or similar to that of aryl methyl sulfides.…”

Electrophilic and nucleophilic pathways in ligand oxide mediated reactions of phenylsulfinylacetic acids with oxo(salen)chromium(V) complexes

“…Additive like 4-phenylpyridine N-oxide (4-PPNO) facilitates faster reaction rates, higher epoxide yields and improved enantio-selectivity [61][62][63][64][65][66][67] in the Mn(III) salen mediated reactions. On the other hand in the epoxidation of olefins [53] and in the oxidation of aryl methyl sulfides [29,68], aryl phenyl sulfides [30,69], sulfoxides [31,32] and arylthioacetic acids [33] by oxo(salen)manganese(V) complexes, the added LOs have no appreciable effect on the reaction rate.…”

“…Although, a large number of reports on the reactivity of oxo metal complexes with nitrogen bases as additives [23][24][25][26][27] have appeared in the literature only little interest has been paid by using ligand oxides as additives in these reactions. Even in majority of cases where ligand oxides are used as additive, no effect is observed in epoxidation [28] and sulfoxidation reactions [29][30][31][32][33]. Further, there was no detailed mechanistic study on the oxidation of phenylsulfinylacetic acid (PSAA) except our recent publications on the proximal effects of nitrogen bases with oxo(salen)Cr(V) + ion [34] and Cr(VI) oxidation of PSAA [35] mediated by cetyltrimethylammonium bromide [36], oxalic acid [37] and picolinic acid [38], though PSAA is a versatile synthetic agent used for the synthesis of antibiotics [39] and various organic compounds [40][41][42][43][44].…”