C-H•••π interactions as modulators of carbocation structure - implications for terpene biosynthesis

Density functional theory calculations on geometries and interaction energies for C-H center dot center dot center dot pi interactions involving carbocations are described. C-H bonds involved in strong hyperconjugation are shown to be strong C-H center dot center dot center dot pi donors and their participation in C-H center dot center dot center dot pi interactions with specific geometries is shown to promote large modifications to the structures of carbocations. Implications for terpene biosynthesis are discussed.