Hydroperoxide-dependent epoxidation oxidizing agent

Titanium tetraisopropoxide forms a chiral complex with either (+)-DET or (—)-DET, and this complex serves as the chiral catalyst. In the presence of such a catalyst, an oxidizing agent such as rcrt-butyl hydroperoxide (ROOH, where R = tert-hutyi) can be employed to convert the alkene into an epoxide. The stereochemical outcome of the reaction depends on whether the dural catalyst was formed with (+)-DET or (—)-DET. Both enantiomers of DET are readily available, and either one can be used. By choosing between (+)-DET or (—)-DET, it is possible to control which enantiomer is obtained. 

Reaction conditions depend on the reactants and usually involve acid or base catalysis. Examples of X include sulfate, acid sulfate, alkane- or arenesulfonate, chloride, bromide, hydroxyl, alkoxide, perchlorate, etc. RX can also be an alkyl orthoformate or alkyl carboxylate. The reaction of cycHc alkylating agents, eg, epoxides and a2iridines, with sodium or potassium salts of alkyl hydroperoxides also promotes formation of dialkyl peroxides (44,66). Olefinic alkylating agents include acycHc and cycHc olefinic hydrocarbons, vinyl and isopropenyl ethers, enamines, A[-vinylamides, vinyl sulfonates, divinyl sulfone, and a, P-unsaturated compounds, eg, methyl acrylate, mesityl oxide, acrylamide, and acrylonitrile (44,66). 

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