1.4- diisopropyl

The first practical method for asymmetric epoxidation of primary and secondary allylic alcohols was developed by K.B. Sharpless in 1980 (T. Katsuki, 1980 K.B. Sharpless, 1983 A, B, 1986 see also D. Hoppe, 1982). Tartaric esters, e.g., DET and DIPT" ( = diethyl and diisopropyl ( + )- or (— )-tartrates), are applied as chiral auxiliaries, titanium tetrakis(2-pro-panolate) as a catalyst and tert-butyl hydroperoxide (= TBHP, Bu OOH) as the oxidant. If the reaction mixture is kept absolutely dry, catalytic amounts of the dialkyl tartrate-titanium(IV) complex are suflicient, which largely facilitates work-up procedures (Y. Gao, 1987). Depending on the tartrate enantiomer used, either one of the 2,3-epoxy alcohols may be obtained with high enantioselectivity. The titanium probably binds to the diol grouping of one tartrate molecule and to the hydroxy groups of the bulky hydroperoxide and of the allylic alcohol... 

In general this method is limited to the preparation of symmetrical ethers m which both alkyl groups are primary Isopropyl alcohol however is readily available at low cost and gives high enough yields of diisopropyl ether to justify making (CH3)2CHOCH(CH3)2 by this method on an industrial scale... 

The hazards of working with diisopropyl ether are de scribed in the Journal of Chemical Education p 469 (1963)... 

A second dangerous property of ethers is the ease with which they undergo oxi dation in air to form explosive peroxides Air oxidation of diisopropyl ether proceeds according to the equation... 

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