Epoxidations with calcium hypochlorite

There are many compounds closely related to natural products that are associated with novel syntheses. Dehydrated linalool oxide 891, for example, is conveniently made by chlorination of linalool acetate (28 acetate) with calcium hypochlorite, then cyclization of the allyl chloride 892 with sodium hydroxide and Aliquat 336 in methanol. Once obtained 891 was converted to the dehydrogenated lilac alcohols 893 (R = H). The monoepoxides (on the isopropenyl group) were transformed in a mixture of diacetates that were pyrolyzed to the acetates 893 (R = Ac). Linalool oxide epoxides (894) have... 

Dichlorides and e2thers are the main by-products in this reaction. Treatment with base produces propylene oxide. Specialty epoxides, eg, butylene oxide, are also produced on an industrial scale by means of HOCl generated from calcium hypochlorite and acetic acid followed by dehydrohalogenation with base. 

The dihydrofuran derivative 35 was also employed for the synthesis of ethyl 3-amino-3-deoxy-/3-DL-arafiino-pentofuranoside (40b). The synthesis was accomplished27 in three stages. By the action of calcium hypochlorite on 35, a chlorohydrin intennediate was formed which, on treatment with a base, afforded a mixture of the epoxides 37, 38,... 

Using this methodology for systems with fluorine atoms considerably enriches our knowledge of the properties of olefinic systems. The reagent also plays an important role. Thus calcium hypochlorite is occasionally ineffective in epoxidations of fluoroolefins, whereas lithium tert-butyl peroxide is extremely effective (95JCS(CC)629, 96RCI703). 

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