Reusable chiral macrocyclic Mn(III) salen complexes for enantioselective epoxidation of nonfunctionalized alkenes

Organic carbonates as solvents in macrocyclic Mn(III) salen catalyzed asymmetric epoxidation of non-functionalized olefins

“…After the addition of the substrate, in this case styrene, a spectrum (Z) appeared which closely resemble to the original complex 1 (X). This spectral changes further support our proposition for the formation of Mn O species in the catalytic cycle and is consistent with earlier reports on Mn(III) salen complexes [41,42].…”

New ternary immobilization of chiral sulfonato-(salen)manganese(III) complex for aqueous asymmetric oxidation reactions

“…As for synthetic samples, (R,R)-1,2-Diammoniumcyclohexane mono-(+)-tartrate salt [31], Jacobsen's catalyst ([(R,R)-N,N -bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-diaminato(2-)]manganese(III)chloride) [31], and 3-tert-Butyl-2-hydroxyl-benzaldehyde [32] were synthesized according to literatures. Ionic liquids BMImX (BMIm + = 1-n-butyl-3-methylimidazolium; X − = PF 6 − , BF 4 − ) were prepared in acetone [33], and similarly BMImX (X − = NO 3 − ) was synthesized by the ion exchange reaction of commercial BMImX (X − = Cl − ) with AgNO 3 in aqueous solution. 25 D , where sample concentrations were controlled at 0.01 g mL −1 in distilled water.…”

“…values and conversions were obtained in homogeneous catalysis. Synthetic accessibility, inexpensive experimental cost, and nontoxic property of (salen)Mn(III) aroused extensive attentions, such as macrocyclic complex [6], bearing built-in phase-transfer capability [7], grafted into mesoporous materials [8], fluorous salen [9], or ionic liquids facilitated reactions [10], for the purposes of immobilization, recycling and large-scale production. Because of the nature of heterogeneous reactions including nonlinear kinetic behavior, unequal distribution of or access to reactive centers, and leaching problems as well [11], heterogeneous catalysts, however, often afforded comparatively lower enantioselectivities and conversions than their homogeneous counterparts.…”

Synthesis of a reusable polymer anchored cobalt(II) complex for the aerobic oxidation of alkyl aromatics and unsaturated organic compounds

“…Heterogeneous catalysts have an advantage that at the end of reaction the catalyst can be removed by simple filtration [15,16]. In principle the product is un-contaminated with a transition metal or ligand and allows the catalyst to be recycled into the next reaction.…”