Transpositions a etapes multiples d'epoxydes sesquiterpeniques—I : Action de l'acide formique sur l'epoxyde de cyperene. Correlation entre le cyperene et l'α-cedrene

Cyperene epoxide 2, on treatment with formic acid, gives about ten products of which the two major ones have been isolated and characterised. The allylic alcohol 3 is the product of an allylic rearrangement. The diol 5 is produced by a multistep rearrangement, the mechanism of which is remarkable in that the first elementary step cannot be concerted. The structure of the diol 5 has been confirmed by correlation with α-cedrene.