Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

Abstract

The efficient synthesis of two new stereoisomeric 3-aminocyclooctanetriols and new halocyclitol derivatives of them starting from cis,cis-1,3-cyclooctadiene are reported. Reduction of cyclooctene endoperoxide, obtained by photooxygenation of cis,cis-1,3-cyclooctadiene, with zinc yielded a cyclooctene diol followed by acetylation of the hydroxyl group, which gave dioldiacetate by OsO4/NMO oxidation. The cyclooctane dioldiacetate prepared was converted to the corresponding cyclic sulphate via the formation of a cyclic sulphite in the presence of catalytic RuO4. Reaction of this cyclic sulphate with a nucleophilic azide followed by the reduction of the azide group provided the target, 3-aminocyclooctanetriol. The second key compound, bromotriol, was prepared by epoxidation of the cyclooctene diol with m-chloroperbenzoic acid followed by hydrolysis with HBr(g) in methanol. Treatment of bromotriol with NaN3 and the reduction of the azide group yielded the other 3-aminocyclooctanetriol desired. Hydrolysis of the epoxides with HCl(g) in methanol gave stereospecifically new chlorocyclooctanetriols.