Tert-Butylhydroperoxide

Allylic alcohols can be converted to epoxy-alcohols with tert-butylhydroperoxide on molecular sieves, or with peroxy acids. Epoxidation of allylic alcohols can also be done with high enantioselectivity. In the Sharpless asymmetric epoxidation,allylic alcohols are converted to optically active epoxides in better than 90% ee, by treatment with r-BuOOH, titanium tetraisopropoxide and optically active diethyl tartrate. The Ti(OCHMe2)4 and diethyl tartrate can be present in catalytic amounts (15-lOmol %) if molecular sieves are present. Polymer-supported catalysts have also been reported. Since both (-t-) and ( —) diethyl tartrate are readily available, and the reaction is stereospecific, either enantiomer of the product can be prepared. The method has been successful for a wide range of primary allylic alcohols, where the double bond is mono-, di-, tri-, and tetrasubstituted. This procedure, in which an optically active catalyst is used to induce asymmetry, has proved to be one of the most important methods of asymmetric synthesis, and has been used to prepare a large number of optically active natural products and other compounds. The mechanism of the Sharpless epoxidation is believed to involve attack on the substrate by a compound formed from the titanium alkoxide and the diethyl tartrate to produce a complex that also contains the substrate and the r-BuOOH. ... 

Jewell, S.A., DiMonte, D., Richelmi, P., Bellomo, G. and Orrenius, S. (1986). tert-Butylhydroperoxide-induced toxicity in isolated hepatocytes contribution of thiol oxidation and lipid peroxidation. J. Biochem. Toxicol. 1, 13-22. 

Figure 10. Part of the 1H-NMR spectrum of (a) tcrt-butylhydroperoxide in tolu-ene-dn (0.2 mol/L) and (b) tert-butylhydroperoxide (0.2 mol/L) with added TMP (0.002 mol/L) solvent toluene-ds...

ARCO has developed a process for both enantiomers of glycidol based on the Sharpless epoxidation (Figure 14.5) using the more stable and readily available cumylhydroperoxide instead of tert-butylhydroperoxide [7] the process has been considered for commercial application. 

Table 4.2 Catalytic epoxidation of cyclohexene with anhydrous TBHP (tert-butylhydroperoxide).

Some unstable peroxy esters are also reported. The reaction of pentaphenylphosphine with tert-butylhydroperoxide or silicon and germanium hydroperoxides gave the corresponding peroxy derivatives 56, which cannot be isolated (equation 91). 

Eine asymmetrische Substitution allyl-standiger CHg-Gruppen durch 0-Funktionen gelingt nach Denney et al. 80a), wenn man auf cyclische Olefine tert.-Butylhydroperoxid und Cu(II)-Salze optisch aktiver Carbon-sauren einwirken laBt. 

The formation of methylperoxy intermediates—i.e., the product of a formal insertion of O2 into the metal-methyl bond—was substantiated by the observation of epoxidation of allylic alkoxides (Scheme 6), in analogy to the proposed mechanism for the Sharpless epoxidation utilizing tert-butylhydroperoxide (TBHP). A similar oxygen atom transfer from a coordinated alkylperoxide to olefin was also postulated for the epoxidation of olefins with TBHP catalyzed by Cp Mo(0)2Cl [31]. The use of organomolybdenum oxides in olefin epoxidafion cafalysis (albeit not with O2) has recently been reviewed [32]. 

The oxidation to methyl ketones without cleavage of the double bond was reported recently for a palladium NHC complex [108]. When the authors used the previously described catalyst 13 in THF with dioxygen for the oxidation of styrene they found that together with the phenylmethylketone a significant amount of y-butyrolactone was formed. Analysis of the mechanism led to the conclusion that THF is oxidized to a hydroperoxide species which is the real oxidant. They therefore tried tert-butylhydroperoxide (TBHP) and found immediate conversion without any induction period. Optimized conditions include 0.75 mol % of the previously described dimeric complex... 

Y -conjugation, 304 tert-Butyl carbanion, 109 tert-Butylhydroperoxide, 11 2-Butyne, 296... 

Refs l)Beil-not found 2)R.Criegee H. Dietrich,Ann 560,138(1948) CA 43,6189(1949) tert-Butylhydroperoxide, Oxalic Acid Ester(no... 

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