58319-06-5Relevant academic research and scientific papers
Absolute configuration of 7-epi-sesquithujene
Khrimian, Ashot,Cosse, Allard A.,Crook, Damon J.
experimental part, p. 1414 - 1420 (2011/08/10)
7-epi-Sesquithujene (1) is a bicyclic sesquiterpene isolated from phoebe oil, an essential oil of the Brazilian walnut tree, Phoebe porosa. It is also produced by stressed ash trees and has been shown to elicit strong electrophysiological responses on emerald ash borer, Agrilus planipennis, antennae. In the course of the development of a synthetic 7-epi-sesquithujene lure for field testing against the emerald ash borer, we found that the absolute configuration of this compound had not been determined. We isolate >95% pure 7-epi-sesquithujene from phoebe oil via successive fractionation and conventional and argentation (HPLC) chromatographies. The specific optical rotation of this compound matched that of a synthetic product of known configuration. We also synthesized two other stereoisomers of sesquithujene and developed a chiral GC method to separate all four. Based on the specific rotation, stereoselective syntheses, and chiral GC analyses, 7-epi-sesquithujene present in phoebe oil and white ash was found to have the 2S,6S,7R absolute configuration. This article not subject to U.S. Copyright. Published 2011 by the American Chemical Society.
A gold-catalyzed entry into the sesquisabinene and sesquithujene families of terpenoids and formal total syntheses of cedrene and cedrol
Fuerstner, Alois,Schlecker, Andreas
experimental part, p. 9181 - 9191 (2009/10/01)
A concise entry into the bicyclic cyclopropyl ketone derivatives 5 and 6 by way of a gold-catalyzed Ohloff-Rautenstrauch-type enyne cycloisomerization is described. The required substrates were prepared by an asymmetric addition of the branched allylzinc reagent 21 to the alkynyl aldehyde 17 mediated by the deprotonated bisoxazoline (BOX) ligand 22. Compounds 5 and 6 were then converted into a host of different members of the sesquisabina- and sesquithuja families of terpenoids, inter alia with the aid of iron-catalyzed cross-coupling reactions. As the relative and absolute configuration of 5 and 6 could be unambiguously established, the synthetic samples allowed the previously unknown stereostructures of various such terpenoids to be unraveled, including cis-sesquisabinene hydrate (33), 7-epi-sesquithujene (36), sesquisabinene B (37) and epoxysesquithujene (45). Moreover, the preparation of 6 also constitutes a formal total synthesis of cedrene (11) and cedrol (12).
