Manganese catalysts amination

A variety of metals (e.g., Fe, Ru, Rh, Mn) have been used to effect the reaction when the proper cocatalysts are added, a manganese catalyst (apparently Mn(CO)5 ) is most effective. However, the initial discovery was made with, and the work is generally discussed in terms of, the Fe(CO)s/amine catalysts. The corresponding mechanistic interpretation is given in Scheme 12. Under the conditions of the reaction, the iron exists almost entirely as the anionic HFe(CO)4 (in general, the metals exist as the... 

Catalytic amounts of Co(OAc)2 or Mn(OAc)2 in combination with ferf-butyl hydrogen peroxide (1.2 equiv.) as oxidant proved to be effective for amination of benzoxazoles, benzothiazoles, and 2-phenyl-1,3,4-oxadiazole [95]. It is worth noting that in amination of benzoxazoles with secondary aliphatic amines the cobalt catalyst provides better results, while the manganese catalyst is more effective for a similar reaction with primary alkylamines and ammonia. Also the reactions of benzoxazoles with secondary aliphatic amines or formamides have been performed successfully with Cu(OAc)2 (20 mol.%) and oxygen as oxidant [96]. Other azoles do not react with primary alkylamines in the presence of this oxidant. In contrast, when FeCls was used in 0.25-1 equiv. amounts, amination of benzoxazoles and 2-aryl-1,3,4-oxadiazoles (with the exception of their nitro derivatives) proved to... 

Catalysts used for preparing amines from alcohols iaclude cobalt promoted with tirconium, lanthanum, cerium, or uranium (52) the metals and oxides of nickel, cobalt, and/or copper (53,54,56,60,61) metal oxides of antimony, tin, and manganese on alumina support (55) copper, nickel, and a metal belonging to the platinum group 8—10 (57) copper formate (58) nickel promoted with chromium and/or iron on alumina support (53,59) and cobalt, copper, and either iron, 2iac, or zirconium (62). 

Phenols. Phenols are unreactive toward chloroformates at room temperature and at elevated temperatures the yields of carbonates are relatively poor (< 10%) in the absence of catalysis. Many catalysts have been claimed in the patent Hterature that lead to high yields of carbonates from phenol and chloroformates. The use of catalyst is even more essential in the reaction of phenols and aryl chloroformates. Among the catalysts claimed are amphoteric metals or thek haUdes (16), magnesium haUdes (17), magnesium or manganese (18), secondary or tertiary amines such as imidazole (19), pyridine, quinoline, picoline (20—22), heterocycHc basic compounds (23) and carbonamides, thiocarbonamides, phosphoroamides, and sulfonamides (24). 

Without additives, radical formation is the main reaction in the manganese-catalyzed oxidation of alkenes and epoxide yields are poor. The heterolytic peroxide-bond-cleavage and therefore epoxide formation can be favored by using nitrogen heterocycles as cocatalysts (imidazoles, pyridines , tertiary amine Af-oxides ) acting as bases or as axial ligands on the metal catalyst. With the Mn-salen complex Mn-[AI,AI -ethylenebis(5,5 -dinitrosalicylideneaminato)], and in the presence of imidazole as cocatalyst and TBHP as oxidant, various alkenes could be epoxidized with yields between 6% and 90% (in some cases ionol was employed as additive), whereby the yields based on the amount of TBHP consumed were low (10-15%). Sterically hindered additives like 2,6-di-f-butylpyridine did not promote the epoxidation. 

Amination of alkanes (cyclohexane, heptane, adamantane) was achieved with iron and manganese porphyrin catalysts by tosylimidoiodobenzene to yield tosyl-amino derivatives.200 Selective 1-substitution of adamantane (56% yield) and 2-substitution of heptane (66% selectivity) were reported. 

The oxycarbonylation of phenol in the presence of a palladium catalyst, a tertiary amine and a manganese cocatalyst at room temperature and atmospheric pressure results in the formation of diphenyl carbonate in good yield (equation 184).453... 

Asymmetric imidations of aryl alkyl sulfides with [(tosylimino)iodo]ben-zene, catalyzed by various chiral (salen)manganese(III) complexes, have been investigated in some detail [31,32]. The influence of catalyst structure, solvent, temperature, 3°-amine AT-oxides, and the presence of molecular sieves on product yields and the enantioselectivity of imidation with 17 was evaluated. Enan-tioselectivities as high as 90 % ee and 97 % ee with methyl 2-nitrophenyl sulfide and methyl 2,4-dinitrophenyl sulfide, respectively, were achieved. 

The aziridination of olefins, which forms a three-membered nitrogen heterocycle, is one important nitrene transfer reaction. Aziridination shows an advantage over the more classic olefin hydroamination reaction in some syntheses because the three-membered ring that is formed can be further modified. More recently, intramolecular amidation and intermolecular amination of C-H bonds into new C-N bonds has been developed with various metal catalysts. When compared with conventional substitution or nucleophilic addition routes, the direct formation of C-N bonds from C-H bonds reduces the number of synthetic steps and improves overall efficiency.2 After early work on iron, manganese, and copper,6 Muller, Dauban, Dodd, Du Bois, and others developed different dirhodium carboxylate catalyst systems that catalyze C-N bond formation starting from nitrene precursors,7 while Che studied a ruthenium porphyrin catalyst system extensively.8 The rhodium and ruthenium systems are... 

For the reaction of TDI with a polyether triol, bismuth or lead compounds can also be used. However, tin catalysts are preferred mainly because of their slight odor and the low amounts required to achieve high reaction rates. Carboxylic acid salts of calcium, cobalt, lead, manganese, zinc, and zirconium are employed as cocatalysts with tertiary amines, tin compounds, and tin—amine combinations. Carboxylic acid salts reduce cure time of rigid foam products. Organic mercury compounds are used in cast elastomers and in RIM systems to extend cream time, ie, the time between mixing of all ingredients and the onset of creamy appearance. 

II. 5).92 Barkdoll et al. were successful to hydrogenate bis(4-aminophenyl)methane (100 parts) with use of a cobaltic oxide (10 parts) promoted by calcium hydroxide (15 parts) and sodium carbonate (6.5 parts) at 215°C and 12-22 MPa H2.93 Volf and Pasek obtained a high selectivity to primary amine with a cobalt catalyst modified by manganese (5%)94 in the hydrogenation of stearonitrile at 150°C and 6 MPa H2.95... 

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