Hydroperoxide s

In 1996, Hamann and Hoft were able to obtain 1,2,3,4-tetrahydronaphthyl hydroperoxide (THPO, 16b) in enantiomerically enriched form starting from the racemic mixture by selective decomposition of one enantiomer in the presence of Jacobsen s catalyst 2169. Besides the enantiomerically enriched hydroperoxide (.S )-16b, also the corresponding alcohol (/ )-1 -tetralol (19b) was isolated in enantiomerically enriched form (opposite... 

In this enzymatic transformation, three optically active compounds were prepared in one step. Besides the enantiomerically enriched hydroperoxide (S)-16/17a, also the opposite enantiomer of the corresponding alcohol (R)-19/18a and enantiomerically enriched (S)-sulfoxide 23 could be isolated (equation 13). 

Compared to metal-catalyzed asymmetric epoxidation reactions, asymmetric versions of this reaction without the need of a catalyst (apart from a base) are rarely known. In 2000 Adam and coworkers reported a method for the asymmetric Weitz-Scheffer epoxidation of substituted enones 91 by the secondary, optically active hydroperoxide (S)-(l-phenyl)ethyl hydroperoxide (equation 27, Table 10)137. 

Abbreviations p-CN—DMANO = p-cyano-N,N-dimethylaniline N-oxide CHP = cumyl hydroperoxide S = stereoselective NS = nonstereoselective. 

Cumene hydroperoxide degradation. The degradation of the cumene hydroperoxide proceeds via a carbocation mechanism. In the first step, a pair of electrons on the oxygen of the hydroperoxide s hydroxyl group is attracted to a proton of the H30+ molecule, forming an oxonium ion. 

Figure 9.7 Catalytic cycle for asymmetric epoxidation of allyl alcohol with 9.35 as the precatalyst. The precatalyst is generated in situ and undergoes conversion to 9.36 in the presence of allyl alcohol and r-butyl hydroperoxide. S is a solvent molecule. Conversion of 9.36 to 9.37 involves more than one step. This is not shown for clarity (see Problem 10).

The number presented in Table 1 resulted from accepting the direct thermochemical measurements reported in Reference 17 but using the most current values for the enthalpies of formation of triphenylarsine and r-butyl hydroperoxide s and alcohol s. 

Boron fluoride s. under CFgC002H tert-Butyl hydroperoxide s. under Triton B and Vanadium(lll) octanoate... 

Hydroperoxides s. under Formic acid s. under H2O2 Acetic acid s. under Trifluoroacetic acid s. under H O-y... 

Hydroperoxides s. a. under Vanadium(III) octanoate tert-Butyl hydroperoxide s. under CFfiOOH... 

Trifiuoroacetic anhydride s. under H2O2 Hydroperoxides s. under MoCl ... 

Ammonium acetate s. under TiClg tert-Butyl hydroperoxide s. under (Ac2CH)2VO... 

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