R-Butyl peroxide

ESR measurements on irradiation of 3,3-diethoxycarbonyldiaziridine in r-butyl peroxide showed signals of the diaziridinyl radical (43). The structure of the radical followed from coupling with two N atoms with Qn = 14.2 and Qn = 11.7 g and one proton with Oh = 45.7 g (76TL4205). 

Olefins obtained from petroleum cracking gave mixed dipropylalkylphos-phonates when heated in a similar manner with dipropyl phosphite in the presence of di-r-butyl peroxide for 16 h at 130°C. 

Direct phase-transfer catalysed epoxidation of electron-deficient alkenes, such as chalcones, cycloalk-2-enones and benzoquinones with hydrogen peroxide or r-butyl peroxide under basic conditions (Section 10.7) has been extended by the use of quininium and quinidinium catalysts to produce optically active oxiranes [1 — 16] the alkaloid bases are less efficient than their salts as catalysts [e.g. 8]. In addition to N-benzylquininium chloride, the binaphthyl ephedrinium salt (16 in Scheme 12.5) and the bis-cinchonidinium system (Scheme 12.12) have been used [12, 17]. Generally, the more rigid quininium systems are more effective than the ephedrinium salts. 

Methylation is taken as illustrative of alkylation for comparative purposes in Table 25 however, a wide range of other alkylations have been studied (76MI20503). Photolysis of di-r-butyl peroxide in a mixture of cyclohexane and pyridine gives cyclohexylation (equation 170) (7lCR(C)(272)854>. The relative rates for homolytic substitution of pyridines by cyclic alkyl radicals have been obtained (74JCS(P2)1699). A striking contrast can be seen (Table 26)... 

Hydroperoxides and peroxides oxidize primary and secondary aliphatic amines to imines. Thus f-butyl hydroperoxide oxidizes 4-methyl-2-pentyl-amine to 2-(4-methylpentylidene)-4-methyl-2-pentylamine in 66% yield [29]. Di-r-butyl peroxide reacts in a similar manner [29]. However, this reaction is... 

The HPLC method with CLD described in Section V.B.2.C for determination of hydroperoxides using luminol (124) with hemin (75a) catalysis is ineffective with dialkyl peroxides, such as di-r-butyl peroxide, cumyl propyl peroxide and cumyl 3-phenylpropyl peroxide. However, for a certain set of experimental conditions, cumyl allyl peroxide can be determined, but the sensitivity is much lower than for hydroperoxides164. 

The compounds 43, 45, 48b and 48c gave the corresponding disiloxanes in quantitative yields, and BTSP is converted into hexamethyldisiloxane, 44, formed from difluorote-tramethyldisiloxane. The reaction of 44 with BTSP was not inhibited by 2,4,6-tri(/-butyl)phenol. Compound 48a did not react with di-r-butyl peroxide, which is the carbon analog of BSTP, suggesting an important role of vacant d-orbitals of the silicon atom. The Si—Si oxidation of compound 49 with BSTP proceeds quantitatively and in a stereospecific fashion (equation 72)63. 

METHYL KETONES AUyltrimethyl-silane, Bis(acetonitrilo)chloronitro-palladium (11). Dicarb ony lbis( triphenyl-phosphine)nickel. Dichloro-dicyano-benzoquinone. Hydrogen peroxide-Palladium acetate. Meldrum s acid. Palladium r-butyl peroxide trilluoro-acctate. Palladium tl) chloride. 

Di-/-butyl-4-methylpyridine, 160 Di-/-butyl nitroxide, 160-161 Di-r-butyl peroxide, 131... 

Deoxygenation of ROH. Acetates, primary, secondary, or tertiary, are deox-> genated when heated with 1 in the presence of a radical initiator, di-r-butyl peroxide (DTBP). Yields using (C6H5)3SiH in place of 1 are definitely lower. The presence of a double bond in the substrate can lower yields owing possibly to hydrosilylation. 

Many organic peroxides and hydroperoxides are known.30 Peroxo carboxylic acids (e.g., peroxoacetic acid, CH3CO OOH) can be obtained by the action of H202 on acid anhydrides. Peroxoacetic acid is made as 10 to 55% aqueous solutions containing some acetic acid by interaction of 50% H202 and acetic acid, with H2S04 as catalyst at 45 to 60°C the dilute acid is distilled under reduced pressure. It is also made by air oxidation of acetaldehyde. The peroxo acids are useful oxidants and sources of free radicals [e.g., by treatment with Fe2+(aq)]. Dibenzoyl peroxide, di-r-butyl peroxide, and cumyl hydroperoxide are moderately stable and widely used as polymerization initiators and for other purposes where free-radical initiation is required. 

Chlorohydroxylotion of alkenes. Anhydrous -butyl hydroperoxide or di-r-butyl peroxide (1, 211-212) in the presence of TiCh effects chlorohydroxylation of alkenes. 

Reduction of aryl and alkyl halides.5 This reaction can be conducted in generally good yield with LiAlH4 by a free-radical process initiated by irradiation of di-r-butyl peroxide. The order of reactivity of aryl halides is Arl > ArBr > ArCl > ArF. Alkyl and cycloalkyl halides are reduced efficiently, but vinyl bromides are reduced in only modest yield. 

Under similar conditions chromium(VI) oxide and PCC woe found to be less effective. Other cooxidants were also examined hydrogen peroxide gives unacceptable amounts of overoxidation of aldehydes, whilst t-butyl hydroperoxide, di-r-butyl peroxide and benzoyl peroxide all failed as cooxidants. 

Mo02(acac)2 and r-butyl peroxide when dissolved in benzene form a reagent that can be used for the specific cleavage of silyl enol ethers. For example, the silyl ether of p-ionine is selectively deaved as indicated in equation (35), to give -(2,6,6-trimethylcyclohexyl)acrylicacid. 

Epoxidation of allyhc and homoallylic alcohols not part of the diene complex can be achieved using the Sharpless r-butyl hydroperoxide/vanadium acetylacetonate protocol. Dihydroxylation of alkenes adjacent to the diene complex using osmium tetraoxide-r-butyl peroxide has been reported... 

The thermal decomposition, of di- r -butyl peroxide has been fairly extensively studied in order to obtain the dissociation energy of the peroxide link, which is expected to be the weakest in the molecule. Milas and Surgenor347 found that the only products of decomposition in the gas phase at 250G were ethane and acetone, which suggests a simple bond splitting mechanism, followed by very straightforward radical reactions,... 

The pyrolysis of di-/ r/-butyl peroxide has been studied by several workers (Section 4.2). The value of 37 kcal for Z)(0-0) is probably correct 24, The error found in Tossing and Tickner s activation energies is probably not present at the temperature used... 

The substitution of aluminum by oxygen can be effected by various peroxide derivatives, such as di-r-butyl peroxide, benzoyl peroxide and r-butyl perbenzoate. The main reaction is accompanied by telltale free-radical side reactions, such as the formation of RR from R3AI, which become major pathways with aryl and vinyl compounds. Oxidation of alkenyl derivative (56) with r-butyl perbenzoate yields 45% of a mixture of cis and trans ethers (57 equation 44). As of yet there is no generally applicable, highly efficient method for oxidizing vinylaluminum compounds. 

Single fluorine atoms in aromatic fluoro compounds such as p-fluorotoluene and p-fluoroanisole are replaced by hydrogen using lithium aluminum hydride in the presence of di-r-butyl peroxide under irradiation (equation 37). ... 

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