Efficient aerobic epoxidation of alkenes in perfluorinated solvents catalysed by chiral (salen) Mn complexes

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

“…These reactions are generally carried out in a two-phase, water-methylene chloride system, although it has been suggested that using trifluorotoluene rather than methylene chloride improves the yield in some oxidations. 154 Acetone has been recommended to give "milder" reaction conditions. 155 The sodium hypochlorite oxidant is generally added in the form of commercial bleach of varying concentrations, anywhere from 0.3 M to 2 M. 13 It is recommended that fresh bleach be used.…”

Chiral vanadyl salen catalyst immobilized on mesoporous silica as support for asymmetric oxidation of sulfides to sulfoxides

“…In this field, the development of chiral Schiff base ligands received considerable interest since Jacobsen's work [4]. It was shown that the Schiff base ligands are able to coordinate many different metals, and to stabilize them in various oxidation states, enabling the use of Schiff base metal complexes for a large variety of useful catalytic transformations such as asymmetric epoxidation [5][6][7][8], asymmetric sulfide oxidation [9,10], cyclopropanation [11], aziridination [12], Knoevenagel condensation [13], and T. Ben Zid Á I. Khedher (&) Á A. Ghorbel Département de Chimie, Faculté des Sciences de Tunis, Laboratoire de Chimie des Matériaux et Catalyse, 1060 Tunis, Tunisie e-mail: ilyeskhadher@yahoo.com selective hydrogenation reactions under homogenous conditions [14,15]. Due to the advantages of heterogeneous catalysis systems, namely easy catalyst/product separation and simple catalyst recycling, the heterogenization of these homogenous chiral catalysts onto several supports has received great attention in recent years [16][17][18][19][20][21][22].…”

Nitroxide‐Catalyzed Alcohol Oxidations in Organic Synthesis

“…The oxidations are generally carried out in a vigorously stirred two-phase, water-methylene chloride system or in aqueous mixtures with acetone or acetonitrile at room temperature to 0 • C. Trifluorotoluene was suggested as organic phase to improve the yield of some oxidations. 130 As the rate and specificity of nitroxide-catalyzed oxidations are strongly dependent on the pH, the use of phosphate or carbonate buffers is employed to maintain the pH of the reaction typically between 8 and 10. At pH values above about 10, the reaction becomes prohibitively slow, whereas at lower pH values side reactions become prominent.…”