Prediction of a new pathway to presilphiperfolanol.

Quantum chemical calculations on the conversion of farnesyl diphosphate to presilphiperfolanol are described. On the basis of the results of this theoretical study, we predict a new mechanism for presilphiperfolanol formation that involves the intermediacy of nerolidyl diphosphate and an unusual reaction step in which a 1,2-alkyl shift and a transannular alkene attack are combined into a concerted process.