20085-11-4Relevant articles and documents
A multiproduct terpene synthase from medicago truncatula generates cadalane sesquiterpenes via two different mechanisms
Garms, Stefan,Koellner, Tobias G.,Boland, Wilhelm
experimental part, p. 5590 - 5600 (2010/11/20)
Terpene synthases are responsible for a large diversity of terpene carbon skeletons found in nature. The multiproduct sesquiterpene synthase MtTPS5 isolated from Medicago truncatula produces 27 products from farnesyl diphosphate (1, FDP). In this paper, we report the reaction steps involved in the formation of these products using incubation experiments with deuterium-containing substrates; we determined the absolute configuration of individual products to establish the stereochemical course of the reaction cascade and the initial conformation of the cycling substrate. Additional labeling experiments conducted with deuterium oxide showed that cadalane sesquiterpenes are mainly produced via the protonation of the neutral intermediate germacrene D (5). These findings provide an alternative route to the general accepted pathway via nerolidyl diphosphate (2, NDP) en route to sesquiterpenes with a cadalane skeleton. Mutational analysis of the enzyme demonstrated that a tyrosine residue is important for the protonation process.
STABLE CARBOCATIONS FROM TERPENOIDS. I. GENERATION OF CARBOCATIONS FROM NATURAL SESQUITERPENES - DERIVATIVES OF HEXAHYDRONAPHTHALENE
Osadchii, S. A.,Polovinka, M. P.,Korchagina, D. V.,Pankrushina, N. A.,Dubovenko, Zh. V.,et al.
, p. 1070 - 1081 (2007/10/02)
Stable enantio- and diastereomeric carbocations were generated for the first time from optically active sesquiterpenes (-)-α- and (-)-γ-murolenes (I) and (II) and (+)-γ- and (+)-δ-cadinenes (III) and (IV), and their rearrangements in media with various acidities were studied at tempetatures between -120 and 20 deg C.By the reaction of solutions of salts of the stable cations with nucleophiles the transition was realized from unconjugated dienes (I-IV), isolated from the resin of Pinus silvestris L., to the conjugated dienes (-)-zonarene (V), (-)- and (+)-10-epizonarenes (VI, VII), (-)-trans-isocadinene (VIII), and (-)-bicyclosesquiphellandrene (IX), which had been discovered previously in other plant sources.
