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. 

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... 

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. 

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

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... 

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. 

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 ... 

Free radical polymerization of cyclic ketene acetals has been used for the synthesis of polyfy-butyrolactone), which cannot be prepared by the usual lactone route due to the stability of the five-membered ring. The polymerization of 2-methylene-l,3-dioxalane at high temperatures (above 120 °C) gave a high molecular mass polyester [59,79]. Only 50% of the rings opened when the polymerization was carried out at 60 °C, and this led to the formation of a random copolymer. The presence of methyl substituents at the 4- or 5-position facilitated the reaction. The free radical initiators generally used in such polymerizations are ferf-butyl hydroperoxide, ferf-butyl peroxide, or cumene hydroperoxide. The various steps involved are described in Scheme 5 [59]. 

In a recent mechanistic study it was shown that ferf-butyl hydroperoxide acts most likely as a precursor for the formation of a cobalt peroxide intermediate (entry 3)... 

The same group reported additions of tetrahydrofuran or dioxolane 243 to alkynes 242b catalyzed by 10 mol% CuBr and using ferf-butyl hydroperoxide as the oxidant [337]. The reaction does not proceed in the absence of tert-butyl hydroperoxide however, CuBr was not essential as a catalyst, since the additions also proceeded in its absence, although reduced yields of products 244b were obtained. In the catalyzed process a two-electron cycle was proposed to operate since the reaction was not inhibited by BHT, while the uncatalyzed was as expected inhibited. It remains thus unclear what the role of CuBr is and how it is regenerated under the oxidative conditions (see above). 

By-products are formed in subsequent reactions of the terf-alkoxy and tert-alkylperoxy radicals with the hydroperoxide, solvent or olefin. For example, in the metal-catalyzed epoxidation of cyclohexene with ferf-butyl hydroperoxide in benzene, the main by-product was 3-rert-butylperoxy-l-cyclohexene, formed via the sequence433 shown in Eq. (314) [cf. reactions (89)-(94)] ... 

The Sharpless epoxidation uses ferf-butyl hydroperoxide, titanium(IV) isopropoxide, and a dialkyl tartrate ester as the reagents. The following epoxidation of geraniol is typical. 

Several oxidants (Fig. 1) are used as the oxygen source. Examples are bleach (NaOCl), hydrogen peroxide (H202), organic peroxides like dimethyldioxyrane (DMD) or ferf-butyl hydroperoxide (TBHP), peracids like m-chloroperbenzoic acid (mCPBA) or potassium monoperoxysulfate (KHSO5). 

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