A Photo-initiated Wagner-Meerwein Rearrangement. Preliminary communication

Irradiation of the octalin-derived sesquiterpene oxide α-agarofuran in methanol leads to rearrangement to the perhydroazulene system, in addition to simple double-bond migration to β-agarofuran. This rearrangement apparently proceeds through a carbonium-ion-like intermediate, whereas conventional generation of a carbocation leads only to opening of the oxide ring without rearrangement.