Hydroperoxides ferf-butyl hydroperoxide

PdCOTfj CIPr) generated in situ from [Pd(p,-Cl)(Cl)(IPr)]j and AgOTf was reported to catalyse the copper-free Wacker-type oxidation of styrene derivatives using ferf-butyl hydroperoxide (TBHP) as the oxidant (Table 10.7) [41]. Reaction conditions minimised oxidative cleavage of styrene, which is a common side-reaction in Wacker-type oxidations. However, when franx-stilbene was used as a substrate, a significant amount of oxidative cleavage occurred. 

Though relatively stable,explosions have been caused by distillation to dryness [1], or attempted distillation at ambient pressure [2]. In a comprehensive review of the use of the hydroperoxide as a selective metal-catalysed oxygenator for alkenes and alkynes, attention is drawn to several potential hazards in this application. One specific hazard to be avoided stems from the fact that Lucidol TBHP-70 contains 19% of di-ferf-butyl peroxide which will survive the catalysed reaction and may lead to problems in the work-up and distillation [3], A thorough investigation of the stability and explosive properties of the 70% solution in water has been carried out [4]. The anhydrous peroxide as a solution in toluene may now readily be prepared azeotropically, and the solutions are stable in storage at ambient temperature. This solution is now a preferred method for using the anhydrous hydroperoxide [5],... 

In 1965, Denney et al. (98) reported the reaction of a number of alkenes with ferf-butyl hydroperoxide (TBHP) and cupric salts of chiral acids. The use of ethyl camphorate copper complex 144 in the allylic oxidation of cyclopentene provides, upon reduction of the camphorate ester, the allylic alcohol in low yield and low selectivity, Eq. 82. The initial publication only provided the observed rotation of cyclopentenol, but comparison to subsequent literature values (99) reveals that this reaction proceeds in 12% ee and 43% yield (based on the metal complex). 

The asymmetric epoxidation of an allylic alcohol 1 to yield a 2,3-epoxy alcohol 2 with high enantiomeric excess, has been developed by Sharpless and Katsuki. This enantioselective reaction is carried out in the presence of tetraisopropoxyti-tanium and an enantiomerically pure diaUcyl tartrate—e.g. (-1-)- or (—)-diethyl tartrate (PET)—using ferf-butyl hydroperoxide as the oxidizing agent. 

Three examples serve to document the effect of tetrahedral distortion in peroxides, in which the 0-0 unit is connected to an acyclic or to a cyclic framework . 2,5-Dimethyl-2,5-dihydroperoxyhexane (23) (C2/c, 0—0 = 1.47 A, C—O—O—H = 110.6°, Figure 12) exhibits in the solid state two larger and one smaller 0-C-C angle (0-01-02=101.3°, 0-01-03 = 110.5° and 0-01-04 = 110.7°), similar to the situation outlined for ferf-butyl hydroperoxide (1) and triphenylmethyl hydroperoxide (8) (Table 4) °. Oomparable distortions are observed for the peroxide bound 0 atoms in... 

Three peroxides with aromatic substituents have reported enthalpy of vaporization data, all from the same source". The enthalpies of vaporization of cumyl hydroperoxide and ferf-butyl cumyl peroxide are the same, which makes us skeptical of at least one of these values. The calculated b value for cumyl hydroperoxide is 31.5, consistent with the alkyl hydroperoxides. The calculated b value for tert-butyl cumyl peroxide is 15.4 and more than twice that for the mean of the dialkyl peroxides. The structurally related tert-butyl p-isopropylcumyl peroxide has a b value of 8.8 and so is consistent with the other disubstituted peroxides. 

For reaction 3 to replace an oxygen with a methylene group to form a primary alcohol, there are enthalpies of formation for only seven alcohols to compare with the nineteen hydroperoxides, almost all of them only for the liquid phase. The enthalpies of the formal reaction are nearly identical, —104.8 1.1 kJmol, for R= 1-hexyl, cyclohexyl and ferf-butyl, while we acknowledge the experimental uncertainties of 8.4 and 16.7 kJmol, respectively, for the enthalpies of formation of the secondary and tertiary alcohols. We accept this mean value as representative of the reaction. For R = 1- and 2-heptyl, the enthalpies of reaction are the disparate —83.5 and —86.0 kJmol, respectively. From the consensus enthalpy of reaction and the enthalpy of formation of 1-octanol, the enthalpy of formation of 1-heptyl hydroperoxide is calculated to be ca —322 kJ mol, nearly identical to that derived earlier from the linear regression equation. The similarly derived enthalpy of formation of 3-heptyl hydroperoxide is ca —328 kJmol. The enthalpy of reaction for R = i-Pr is only ca —91 kJmol, and also suggests that there might be some inaccuracy in its previously derived enthalpy of formation. Using the consensus enthalpy of reaction, a new estimate of the liquid enthalpy of formation of i-PrOOH is ca —230 kJmoU. ... 

For the formal deoxygenation (decomposition) reaction 5, there is an enthalpy of formation value for every alcohol that matches a hydroperoxide . Using our exemplary groups, R = 1-hexyl, cyclohexyl and ferf-butyl, the liquid enthalpies of reaction are —77.9, —75.0 and —65.6 kJmoR, respectively (there is no liquid phase enthalpy of formation reported for f-butyl peroxide from Reference 4). The secondary hydroperoxides enthalpies of reaction average —77 7 kJmoR. For the three instances where there are also gas phase enthalpies of formation, the enthalpies of reaction are almost identical in the gas and liquid phases. The 1-heptyl (—60.3 kJmoR ) and 1-methylcyclohexyl (—50.6 kJmoR ) enthalpies of reaction are again disparate from the 1-hexyl and tert-butyl. If the enthalpy of reaction 5 for 1-hexyl hydroperoxide is used to calculate an enthalpy of formation of 1-heptyl hydroperoxide, it is —325 kJmoR, almost identical to values derived for it above. The enthalpies of reaction for the liquid and gaseous phases for the tertiary 2-hydroperoxy-2-methylhex-5-en-3-yne are —78.2 and —80.9 kJmoR, respectively. For gaseous cumyl hydroperoxide, the enthalpy of reaction is —84.5 kJmoR. ... 

The three solid phase tetralin and decalin hydroperoxides have enthalpies of reaction that are surprisingly comparable, —93.9 6.4 kJmoR, despite the sometimes large error bars associated with either the peroxide or corresponding alcohol and their differences in structure. Notably, the gas phase reaction enthalpy for the cumyl hydroperoxide is nearly identical to the solid phase reaction enthalpy for the 1-methyl-1-tetralin hydroperoxide, —87.0kJmoR, for these structurally similar compounds and supports the hypothesis that the gas and condensed phase formal reaction enthalpies are nearly the same for all compounds. Flowever, for 2,5-dimethylhexane-2,5-dihydroperoxide, the enthalpies of reaction 5 per hydroperoxy group for the solid and gaseous phase are not close —57 and —76 kJmoR, respectively. Compare them with the enthalpies of reaction for ferf-butyl hydroperoxide of —66 (Iq) and —67 or —78 (g) kJmoR. For the unsaturated counterpart, 2,5-dimethylhex-3-yne-2,5-dihydroperoxide, the solid and gas phase enthalpies of reaction per hydroperoxy group are —64.2 kJmoR and —74.6 kJmoR, respectively. 

As was the case for the alkyl hydroperoxides in reaction 4, the enthalpies of the oxy-gen/hydrocarbon double exchange reaction 8 for dialkyl peroxides are different depending on the classification of the carbon bonded to oxygen. For R = Me, Et and f-Bu, the liquid phase values are —4, 24.6 and 52.7 kJmoR, respectively, and the gas phase values are 0.1, 25.7 and 56.5 kJmoR, respectively. For the formal deoxygenation reaction 9, the enthalpies of reaction are virtually the same for dimethyl and diethyl peroxide in the gas phase, —58.5 0.6 kJ moR. This value is the same as the enthalpy of reaction of diethyl peroxide in the liquid phase, —56.0 kJ moR (there is no directly determined liquid phase enthalpy of formation of dimethyl ether). Because of steric strain in the di-ferf-butyl ether, the enthalpy of reaction is much less negative, but still exothermic, —17.7 kJmol (Iq) and —19.6 kJmol (g). 

TBHP = ferf-butyl hydroperoxide, CHP = cumyl hydroperoxide. 

The first variant works with isobutane as the hydroperoxide precursor, which is oxidized to TBHP by molecular oxygen. During the epoxidation of propene, TBHP is transformed to ferf-butanol, which is converted to methyl ferf-butyl ether. The second procedure employs ethylbenzene, which is oxidized by molecular oxygen to phenyl ethyl hydroperoxide, which transfers an oxygen to propene and so is reduced to phenylethanol. This by-product of the process is converted to styrene, a versatile bulk chemical. 

Oxidation of sulfides and sulfoxides using Oxone dispersed on silica gel or alumina was reported . A study of surface mediated reactivity of Oxone compared its reactivity with that of ferf-butyl hydroperoxide. Oxidation of sulfides to sulfones in aprotic solvents mediated by Oxone on wet montmorillonite or clay minerals proceeds in high yields. Interestingly, when Oxone on alumina is applied for selective oxidation of sulfides in aprotic solvents, the product distribution is temperature-dependent and sulfoxides or sulfones are obtained in good to excellent yields (equation 56) . ... 

The first synthesis of a peroxyphosphonate 68, i.e. ferf-butyl alkyl peroxyphospho-nate 72, was performed by the condensation of the corresponding alkyl alkylphospho-nochloridate with the sodium salt of ferf-butyl hydroperoxide in anhydrous diethyl ether (equation 99) . ... 

Fluoro-oct-1-en-3-one (82) has been synthesized by allylic hydroxylation of vinyl fluoride (Scheme 31) [77,78], Oxidation of vinyl fluoride (83) using 0.5 equiv. of Se02 and 2 equiv. of ferf-butyl hydroperoxide with a catalytic amount of acetic acid followed by elimination formed to 2-fluoroalk-1-en-3-ols (84) in 32% overall yield for three steps. Subsequent pyridinium dichromate-oxidation of 84 yielded 2-fluoro-oct-1-en-3-one (83) in 81% (Scheme 31). 

We were unable to detect any signal which could be assigned to an alkoxy radical in the titanous ion reduction (17, 38) of ferf-butyl hydroperoxide from +25° to — 60°C., nor could an alkoxy radical signal be... 

Ethyl ferf-butyl peroxide was prepared by reaction of the sodium salt of f erf-butyl hydroperoxide (purified by recrystallization and frequent washings of acetone to free it from terf-butyl peroxide) and diethyl sulfate (23). The peroxide was purified by distillation (35-36°C. and 80-mm. pressure). NMR analysis (Perkin Elmer R60) showed that the samples used contained less than 1% ferf-butyl peroxide and negligible... 

M ferf-Butyl hydroperoxide solution in toluene (0.375 mL, 1.5 mmol) ( )-Ethyl cinnamate (220.3 mg, 1.25 mmol)... 

Peroxy esters 67 were prepared in situ by the reaction of phosphonochloridate and ferf-butyl hydroperoxide in diethyl ether. The peroxy ester 67 (R = Ph) is stable for several days at 5 °C in diethyl ether. Most peroxyphosphates 67 with an RO group other than ferf-butylperoxy are unstable even for short periods264. This synthetic method was successfully applied for synthesis of ring peroxyphosphates 70 and 71 as colorless oils. They are very unstable and decompose at 25 °C to yield polymeric products and volatile side products264. 

Peroxyphosphonate can be prepared by a similar reaction in the presence of pyridine265 instead of the sodium salt of the hydroperoxide. Peroxyphosphonates 72 are generally synthesized by the condensation of the corresponding phosphinic chloride with the sodium salt of ferf-butyl hydroperoxidate in a neutral solvent in the presence of sodium sulfate, or alternatively, by the reaction of ferf-butyl hydroperoxide with phosphinic chloride in the presence of pyridine266. 

Reagents and conditions were 5 ml. solution prepared from 17 ml. ferf-butyl hydroperoxide (97% purity), 100 ml. olefin, and 0.02 gram molybdenum hexacarbonyl in a sealed tube for 30 minutes. 

Alkoxyalkyl Alkyl Peroxides. ferf-Butyl tetrahydropyran-2-yl peroxide (1, where R3 = tert - butyl. H = OR4, R1 = H, R2 and R4 = 1,4 -butanediyl, has been isolated. This is one of many examples of alkoxyalkyl alkyl peroxides which may be prepared by reaction of hydroperoxides with vinyl ethers. 

Peroxide end groups can also be formed by polymerization of a monomer in the presence of ferf-butyl hydroperoxide as initiator and small quantities of a copper-II salt, e. g. copper octoate 128). The reaction scheme is ... 

Scheme 8.2 The sequential epoxidation of 2,5-di-ferf-butyl-1,4-benzoquinone with ferf-butyl hydroperoxide.

The sequential epoxidation of 2,5-di-ferf-butyl-1,4-benzoquinone with ferf-butyl hydroperoxide is shown in Scheme 8.2. In the experiments discussed below, Triton-B was added to the mixture as a catalyst, and the basic reaction model is written as Equations 8.24 ... 

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