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.