13C NMR detection of delocalized C10-allylic cation in the biosynthesis of farnesyl diphosphate

Abstract

A new signal was observed at δ 164.5 in the ¹³C NMR spectrum obtained by the enzymatic condensation of [1-¹³C]geranyl diphosphate with isopentenyl diphosphate by farnesyl diphosphate synthase; the signal was assigned to C-1 of a delocalized C₁₀-allylic cation on the basis of MO calculations, the ¹³C NMR spectrum of [1-¹³C]geraniol in magic acid (FSO₃H–SbF₅) and ¹³C NMR spectra of the enzyme reaction under reversible inhibition conditions.