MOLECULAR REARRANGEMENTS OF HIGHLY FUNCTIONALIZED TERPENES. AN UNIQUE REACTIVITY OF BICYCLIC FRAMEWORK AND POLIENIC CHAIN INHIBITION UNDER SUPERACIDIC TREATMENT

Abstract

Synthesis of polyfunctional triterpene derivative [8(27),13E,17E,21E]-15-phenylsulfonyl-16-oxobicyclofarnesylfarnesol benzyl ether (8) from commercially available monoterpene geraniol and diterpene manool has been accomplished in 73% yield and its chemical transformation in superacid medium has been investigated. An unexpected rearrangement of 8 occurred, which involved methyl migration in the bicyclic fragment and total inhibition of the lateral polienic chain. A new bicyclic triterpene product [5(10),13E,17E,21E]-15-phenylsulfonyl- 16-oxo-30(10→9)-abeo-bicyclofarnesylfarnesol benzyl ether (9), with rearranged new carbon skeleton has been obtained. Its bicyclic moiety is analogous to this of a natural triterpene neopolypodatetraene.

Keywords

• triterpenes
• synthesis
• superacid
• isomerization