473-13-2Relevant academic research and scientific papers
Total synthesis and stereochemistry of 13-hydroxy-α-eudesmol
Chen, Yonggang,Xiong, Zhaoming,Zhou, Gang,Liu, Lijun,Li, Yulin
, p. 1923 - 1928 (1998)
The first total synthesis of both C-11 epimers of 13-hydroxy-α-eudesmol 1a and 1b by the use, as a key reaction, of the Sharpless asymmetric dihydroxylation of alkene 7 is presented. The absolute configuration of natural 13-hydroxy-α-eudesmol is established through comparison of the 1H NMR spectrum of natural diol and synthetic diols. In our synthesis another natural product (+)-α-selinene 2 has also been accomplished.
Absolute configuration of helminthogermacrene
Adio, Adewale Martins,Paul, Claudia,Tesso, Hailemichael,Kloth, Petra,Koenig, Wilfried A.
, p. 1631 - 1635 (2007/10/03)
The absolute configuration of the sesquiterpene hydrocarbon helminthogermacrene is established. Helminthogermacrene is an (E,Z)-configurational isomer of germacrene A and thus undergoes similar transformations forming elemenes via Cope rearrangement and yielding bicyclic systems via acid catalyzed reactions. The reaction products are investigated using enantioselective GC and extensive NMR measurements (1H-; 1H1H-COSY; HSQC; HMBC and NOE-experiments). In addition, NMR data of related compounds isolated during the course of this investigation not yet reported in literature are given.
Germacrenes from fresh costus roots
De Kraker, Jan-Willem,Franssen, Maurice C.R,De Groot, Aede,Shibata, Toshiro,Bouwmeester, Harro J
, p. 481 - 487 (2007/10/03)
Four germacrenes, previously shown to be intermediates in sesquiterpene lactone biosynthesis, were isolated from fresh costus roots (Saussurea lappa). The structures of (+)-germacrene A, germacra-1(10),4,11(13)-trien-12-ol, germacra-1(10),4,11(13)-trien-12-al, and germacra-1(10),4,11(13)-trien-12-oic acid were deduced by a combination of spectral data and chemical transformations. Heating of these compounds yields (-)-β-elemene, (-)-elema-1,3,11(13)-trien-12-ol, (-)-elema-1,3,11(13)-trien-12-al, and elema-1,3,11(13)-trien12-oic acid respectively, in addition to small amounts of their diastereomers. Acid induced cyclisation of the germacrenes yields selinene, costol, costal, and costic acid respectively. It is highly probable that the elemenes reported in literature for costus root oil are artefacts.
Total Synthesis of rac-Sesquiterpenoid AE 1
Schinzer, Dieter,Fessner, Klaus,Ruppelt, Martin
, p. 139 - 144 (2007/10/02)
rac-Sesquiterpenoid AE 1 (rac-1) can be obtained in an 11-step sequence starting from 5-methylresorcinol (2).The key compound 9 is synthesized by the use of a diastereoselective dienone cyclization with the allylic silane 8.Subsequent transformation of 9 leads to rac-1. Key Words: Sesquiterpenoid AE 1 / Dienone cyclization / Allylsilane
TOTAL SYNTHESIS OF RACEMIC SELINA-3,7(11)-DIENE, α-SELINENE AND α-EUDESMOL
Chou, Ta-shue,Lee, Shwu-Jiuan,Yao, Nai-Kwang
, p. 4113 - 4124 (2007/10/02)
Three natural products of the eudesmane family, selina-3,7(11)-diene, α-selinene and α-eudesmol, have been synthesized using a common strategy.The key steps involved in the strategy include the direct deprotonation/alkylation of isoprenyl sulfone and the intramolecular Diels-Alder reaction.
A NEW ROUTE FOR THE CONVERSION OF CARVONE INTO EUDESMANE SESQUITERPENES
Caine, Drury,Stanhope, Bruce
, p. 5545 - 5556 (2007/10/02)
The β-hydroxy-α-phenylsulfenyl ketone 2, derived from S-(+)-carvone, was treated with 2 equivalents of the Wittig-Horner phosphine oxide derivative 6 followed by excess methyl iodide to give a ca. 2:3 mixture of the E and Z α-phenylsulfenyl ketones 3a and 3b.The mixture of sulfides was oxidized to the corresponding sulfoxides 3c,d with m-chloroperbenzoic acid.When this mixture refluxed in benzene, elimination of phenylsulfinic acid occured and the intermediate E diene derivative 4a underwent an intramolecular Diels-Alder reaction to give the trans-octalone 5a, the cis-octalone 5c, and another product believed to be the trans-octalone 5b in a 60:28:12 ratio.The Z diene derivative 4b was recovered under these reaction conditions.Wolff-Kishner reduction of the octalone mixture gave (-)-α-selinene (10) as the major product along with the cis-octalin 11 and other unidentified minor products.When the Z diene derivative 4b was heated in toluene at 150 deg C for 48 h, a mixture of octalones having the same composition as that produced above was obtained.Likewise, when the 2:3 mixture of sulfoxides 3c and 3d was heated in toluene at 150 deg C, the same mixture of octalones was produced.Apparently, at the higher temperature, the Z diene derivative 4b isomerized to the E isomer 4a which ultimately underwent the intramolecular Diels-Alder reaction.
