Stereoselective Synthesis of Bishomo-inositols as Glycosidase Inhibitors

For the synthesis of various bishomo-inositol derivatives, 1,3,3a,7a-tetrahydro-2-benzofuran was used as the key compound. For further functionalization of the diene unit, the diene was subjected to photooxygenation, epoxidation, and cis-hydroxylation reactions. The endoperoxide linkage was cleaved by thiourea. The remaining double bond was subjected to epoxidation and cis-hydroxylation reactions. The epoxide rings and tetrahydrofuran rings formed were opened by acid-catalyzed reaction with sulfamic acid. The combination of these reactions resulted in the formation of various new inositol derivatives such as bishomo-chiro-inositol, bishomo-myo-inositol, and two isomeric bishomo-allo-inositols.