Tert-butyl hydroperoxide , copper

Very recently, the chemoenzymatic preparation of nootkatone from valencene was described [150]. Nootkatone was prepared from valencene by copper(I) iodide catalysed oxidation with tert-butyl hydroperoxide and hydroxylated at C-9 by Mucor plumbeus and Cephalosporium aphidicola. 

Rothenberg, G., Feldberg, L., Wiener, H., Sasson, Y. Copper-catalyzed homolytic and heterolytic benzylic and allylic oxidation using tert-butyl hydroperoxide. J. Chem. Soc., Perkin Trans. 21998, 2429-2434. 

Copper Catalysts Copper is an excellent catalyst for nitrogen transfer reactions via copper-nitrene intermediates. Benzylic hydrocarbons are selectively converted to the corresponding sulfonamides [40]. The intermolecular amidation of saturated C—H bonds of cyclic ethers has been reported using TsNH2-PhI(OAc)2 or PhI=NTs as the nitrene source [41]. The copper-catalyzed amidation of unactivated sp3 C—H bonds adjacent to a nitrogen atom has also been achieved using tert-butyl hydroperoxide or... 

Other hydrogen transfer reactions of glycine derivatives have been used to introduce functional groups at the a-position. For example, reactions with bromine or A -bromosuccinimide, fert-butyl perbenzoate in the presence of a copper catalyst, and tert-butyl hydroperoxide and formate, have been used to produce a-bromo-, benzoyloxy- and carboxy-substituted glycine derivatives, respectively (Scheme 2) [12-14]. 

Redox catalysts are particularly active.354 A few drops of a 60% solution of tert-butyl hydroperoxide in dimethyl phthalate are added to the batch in the cold, followed at about 70° by 1-2 drops of a concentrated solution of cobalt(n) or copper(n) dodecanoate. The reaction then begins at once and continues smoothly. 

Heterocycle construction by using palladium, iron, copper, or iodine/ tert-butyl hydroperoxide 13SL1322. 

Another oxidative Ugi-3CR was reported by Xie et al. for the synthesis of a-amino imides from tertiary amines by direct activation of sp C—Hs adjacent to nitrogen using an oxidant (tert-butyl hydroperoxide (TBHP)) and a copper salt [23]. Notably, the reaction could be conducted under mild... 

Oxidation with tert-Butyl Hydroperoxide Catalyzed by Copper(II) and Iron(H) Complexes... 

Other Heteroatom Nucleophiles. Alcohols and carboxylic acids also add to metal-activated alkenes, and processes for the industrial conversion of ethylene to vinyl acetate and acetals are well established. However, these processes have not been extensively used with more cort5)lex alkenes. In contrast, a number of intramolecular versions of the processes have been developed, a few examples of which are given here. Allylphenols cyclize readily in the presence of palladium(II) to form benzofurans (eq 4). Catalytic amounts of palladium acetate can be used if the reaction is carried out under 1 atm of molecular oxygen with copper diacetate as cooxidant, or in the presence of tert-butyl hydroperoxide. If instead of palladium acetate a chiral jr-allylpalladium acetate complex is used, the cyclization proceeds to yield 2-vinyl-2,3-dihydrobenzofuran with up to 26% ee. ... 

Haloform reactions are generally performed with halogens in the presence of hydroxide [251] or directly with hypohalites [252]. Alternative methods affording carboxylic acids from methyl ketones (or other enolizable substrates) include the aerobic oxidation in the presence of a catalytic amount of dinitrobenzene [253] with a base in a dipolar aprotic solvent such as DMF [254] or HMPT (hexamethylphospho-ric triamide) [255, 256] and the use of stoichiometric quantities of hypervalent iodide derivatives [95, 257] or nitrosylpentacyanoferrate [258]. Furthermore, metal catalysts can be used, and systems such as tert-butyl hydroperoxide in the presence of rhenium oxide [259], oxygen in combination with a copper complex [260], heteropolyacids [261] and Mn"/Co" systems [262] were found to be applicable. Finally, aryl ketones are selectively oxidized to aliphatic carboxylic acids by treatment with periodate [81] in the presence of ruthenium trichloride [263]. 

Some fabrication processes, such as continuous panel processes, are run at elevated temperatures to improve productivity. Dual-catalyst systems are commonly used to initiate a controlled rapid gel and then a fast cure to complete the cross-linking reaction. Cumene hydroperoxide initiated at 50°C with benzyl trimethylammonium hydroxide and copper naphthenate in combination with tert-butyl octoate are preferred for panel products. Other heat-initiated catalysts, such as lauroyl peroxide and tert-huXyi perbenzoate, are optional systems. For higher temperature molding processes such as pultrusion or matched metal die molding at temperatures of 150°C, dual-catalyst systems are usually employed based on /-butyl perbenzoate and 2,5-dimethyl-2,5-di-2-ethylhexanoylperoxy-hexane (Table 6). 

METHYL STYRENE or 3-METHYL STYRENE or 4-METHYL STYRENE or m-METHYL STYRENE or p-METHYL STYRENE mixed Isomers (25013-15-4) C,H,o Flammable liquid. Forms explosive mixture with air (flash point 125°F/51°C). An inhibitor, usually 10 to 50 ppm of tert-butyl catechol, must be present in adequate concentrations to avoid explosive polymerization. Violent reaction with strong oxidizers, strong acids, peroxides and hydroperoxides. Incompatible with catalysts for vinyl or ionic polymers aluminum, aliuninum chloride, ammonia, aliphatic amines, alkanolamines, caustics, copper, halogens, iron chloride, metal salts (e.g., chlorides, iodides, sulfates, nitrates). The uninhibited monomer vapor may block vents and confined spaces by, forming a solid polymer material. On small fires, use dry chemical powder (such as Purple-K-Powder), foam, or CO extinguishers. a-METHYL STYRENE (98-83-9) C,H, Flammable liquid. Forms explosive mixture with air [explosion limits in air (vol %) 0.9 to 6.1 flashpoint 129°F/54°C autoignition temp 1066°F/574°C Fire Rating 2]. Easily polymerizable. Unless inhibited, forms unstable peroxides. Reacts with heat and/or lack of appropriate inhibitor concentration. Reacts with catalysts for vinyl or ionic polymerization, such as aluminum, iron chloride or 2,5-dimethyl-2,5-di(ieri-butylperoxy)hexane. Violent reaction with... 

Effect of Various Additives. From the results mentioned above, it is evident that the copper stearate is converted to inhibitors by the interactions of oxidation products, and the oxygen uptake appears to level oflF after a certain time. Thus, the effects of model compounds of oxidation products (n-octylaldehyde, n-octanoic acid, 2-octanone, n-octanol, and n-octanoic aCid methyl ester), tert-hutyl hydroperoxide, and di-ter -butyl peroxide on the thermal oxidation of the polypropylene in trichlorobenzene were examined. 

Richardson [334] also examined the decomposition of tert-hntyl hydroperoxide in the presence of copper(II) 2-ethylhexanoate in chlorobenzene at 50 C. The product composition was approximately 87% cr/-butyl alcohol, 11% di-r-butyl-peroxide, 1-2% acetone and a large amount of oxygen. Reaction is 0.55 order in copper salt and less than first order dependence on hydroperoxide was observed. Trapping experiments with 2,6-di-r-butyl-p-cresol indicate a radical mechanism. The kinetic data indicate a mechanism involving a hydroperoxide complex, [Cu(II)2(ROOH)2], and NMR spectral evidence was obtained for axial hydroperoxide ligands [334]. 

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