Novel rearrangements of sesquiterpenoid panasinsane derivatives under acidic conditions

The sesquiterpenoid panasinsane derivatives 11 and 14-16 have been prepared from caryophyllene oxide (7). The novel rearrangement reactions of compoun ds 11 and 14 under TCNE-catalyzed solvolysis conditions and the reactions o f compounds 15 and 16 under superacid conditions (HSO3F/ Et2O, -63 degreesC ) have been investigated. The ginsenol derivative 17 is obtained from compo unds 11 and 14 under TCNE-catalyzed conditions. The rearrangement of compou nds 15 and 16 under superacid conditions leads to the novel sesquiterpene d erivatives (1S,4S,7S,10S,11S)-3,3,10,11-tetramethyltricyclo [5.3.1.0(4,10)] undecan-1,11-yl sulfate (19) and (1S,4S,5S,8S)-2,2,4,8-tetramethyl tricycl o[3.3.2.1(4,8)]undecan-11-one (20). The influence of the secondary hydroxyl group at C-5 of the panasinsane derivatives on the course of these rearran gements is discussed.