Acid-induced rearrangement of triterpenoid hydrocarbons belonging to the hopane and migrated hopane series.

Abstract

The acid-catalyzed rearrangement of triterpenoid monoenes belonging to the hopane and migrated hopane series with sulfuric acid and boron trifluoride etherate was investigated. By selecting the reaction conditions, a variety of the monoenes of these series, including three new compounds, 9βH-fern-7-ene (3c), 8βH-fern-9 (11) -ene (4b), and adian-5 (10) -ene (5b), were obtained. For comparison, oleanenes and migrated oleanenes were also subjected to the same reaction.