Convenient asymmetric (salen)Mn(III)-catalyzed epoxidation of unfunctionalized alkenes with hydrogen peroxide using carboxylate salt cocatalysts

Epoxidation studies of 2-styrylchromones using jacobsen's catalyst and hydrogen peroxide and iodosylbenzene as oxidants

“…Only a few years after this key publication an asymmetric version of this epoxidation was reported by the groups of Jacobsen [18] and Katsuki [19] using chiral Mn(III)-salen complexes as catalyst. Iodosylbenzene [17][18][19][20][21][22][23] and sodium hypochlorite [24][25][26] are the most frequently used terminal oxidants but other oxygen sources such as hydrogen peroxide [27][28][29][30], dimethyldioxirane (DMD) [31][32][33], Oxone ® [34], tetrabutylammonium monopersulfate [35], tetrabutylammonium periodate [36], mchloroperoxybenzoic acid [37] and even molecular oxygen [38] have been reported. Iodosylbenzene is a polymeric substance, prepared by base-induced hydrolysis of the commercially available iodobenzene diacetate, and the role of the catalyst in homogeneous catalysis is to solubilise it in its monomeric form.…”

The Protein Environment Drives Selectivity for Sulfide Oxidation by an Artificial Metalloenzyme

“…Indeed, in the case of hydrogen peroxide-mediated epoxidation, the reactivity of Mn-salen complexes was greatly improved when imidazole was bound in an apical position. [43] Moreover, the absence of intense CD transitions related to the ligand-to-metal charge transfer (LMCT) bands of the inorganic complex in the CD of the hybrid suggests no direct coordination of the Mn. On the other hand, the importance of the R groups for the selectivity of the binding indicates that hydrogen bonding exists between the R groups and residues of the cleft.…”

Epoxidation Studies of 2‐Styrylchromones Using Jacobsen′s Catalyst and Hydrogen Peroxide and Iodosylbenzene as Oxidants.

“…Only a few years after this key publication an asymmetric version of this epoxidation was reported by the groups of Jacobsen [18] and Katsuki [19] using chiral Mn(III)-salen complexes as catalyst. Iodosylbenzene [17][18][19][20][21][22][23] and sodium hypochlorite [24][25][26] are the most frequently used terminal oxidants but other oxygen sources such as hydrogen peroxide [27][28][29][30], dimethyldioxirane (DMD) [31][32][33], Oxone ® [34], tetrabutylammonium monopersulfate [35], tetrabutylammonium periodate [36], mchloroperoxybenzoic acid [37] and even molecular oxygen [38] have been reported. Iodosylbenzene is a polymeric substance, prepared by base-induced hydrolysis of the commercially available iodobenzene diacetate, and the role of the catalyst in homogeneous catalysis is to solubilise it in its monomeric form.…”

“…Optimization experiments were done with the parent compound 2a using dichloromethane/methanol (1:1, v/v) mixture as solvent, since it is known that the use of this mixture is important to solubilize the substrate and to mix it with hydrogen peroxide [28,30]. Surprisingly, treatment of 2a with an excess of hydrogen peroxide or alkaline hydrogen peroxide, with or without catalyst 1, at room temperature failed to give any epoxide.…”