Rearrangements of epoxides of some acyclic terpenoids in acidic media

2,3-Epoxygeraniol undergoes dissimilar rearrangements in contact with liqui d superacids at low temperature or on solid superacids at room temperature due to different location of the arising cationic center depending on the s uperacid character. 2,3-Epoxynerol, 6,7-epoxycitronellol, and 6,7-geranyl a cetate on ZrO2SO42 afford the corresponding ketones via epoxy ring opening followed by 1,2-hydride shift. With 6,7-geranyl acetate 7-oxanobornane form ed as a minor product. The mode of generation of the cationic center (eithe r the olefin protonation or the epoxy ring opening) affects the rearrangeme nt direction at similar conditions.