It is proposed that the biosynthesis of the sesquiterpene valerenadiene, a key intermediate in the biosynthesis of a sedative in valerian, involves cyclopropane and not cyclobutane intermediates and includes as a key step a cyclopropylcarbinylcation-cyclopropylcarbinylcation rearrangement analogous to the one observed in the conversion of presqualene to squalene in triterpene and steroid biosynthesis. Similar mechanisms are proposed for the biosynthesis of the related sesquiterpenes pacifigorgiol, tamariscene and (+)-pacifigorgia-1,10-diene.
YeoY-S, NyboS.E., ChittiboyinaA.G., WeerasooriyaA.D., WangY-H, Gongora-CastilloE., VaillancourtB., BuellC.R., DellaPennaD., CelizM.D., JonesA.D., WurteleE.S., RansomN., DudarevaN., ShaabanK.A., TibrewalN., ChandraS., SmillieT., KhanI.A., CoatesR.M., WattD.S., ChappellJ. (2013) Functional identification of valerena-1,10-diene synthase, a terpene synthase catalyzing a unique chemical cascade in the biosynthesis of biologically active sesquiterpenes in Valeriana officinalis. Journal of Biological Chemistry, 288, 3163–3173.
2.
PyleB.W., TranH.T., PickelB., HaslamT.M., GaoZ., MacNevinG, VederasJ.C., KimS-U, RoD-K. (2012) Enzymatic synthesis of valerena-4,7(11)-diene by a unique sesquiterpene synthase from the valerian plant (Valeriana officinalis). FEBS Journal, 279, 3136–3146.
3.
PaulC., KonigW.A., MuhleH. (2001) Pacifigorgianes and tamariscene as constituents of Frallania tamarisci and Valeriana officinalis. Phytochemistry, 57, 307–313.
4.
BlaggB.S.J., JarstferM.B., RogersD.H., PoulterC.D. (2002) Recombinant squalene synthase. A mechanism for the rearrangement of presqualene diphosphate to squalene. Journal of the American Chemical Society, 124, 8846–8853.
5.
BuchiG., WittenauS., WhiteD.M. (1959) Terpenes X. The constitution of maaliol. Journal of the American Chemical Society, 81, 1968–1980.
6.
BatesR.B., PaknikarS.K. (1965) Valerenal. Chemistry and Industry, 1731