23527-07-3Relevant articles and documents
Synthesis of (+)-8-deoxyvernolepin and its 11,13-dihydroderivative. A novel reaction initiated by sulfene elimination leads to the 2-oxa-cis-decalin skeleton
Barrero, Alejandro F.,Oltra, J. Enrique,Alvarez, Miriam,Rosales, Antonio
, p. 5461 - 5469 (2007/10/03)
The title compounds are interesting candidates for antifungal screening. This paper describes the enantiospecific synthesis of these compounds starting from (+)-costunolide isolated from a commercially available extract. We used two novel reactions as key synthetic steps in this work: the acid-induced cyclization of an δ,ε-epoxy ester, which stereoselectively gave a hydroxymethyl-substituted δ-lactone, with the hydroxyalkyl group in the desired β-equatorial disposition, and a reaction cascade, initiated by a base-promoted sulfene elimination, which led to a 10-oxiranyl-2-oxa-cis-decalin from the mesylate of a trans-fused δ-lactone. We also found that the reaction between selenium dioxide and the 1,5-diene system of elemanolides gave selenadecalins analogous to natural eudesmanolides. Our results prove that the synthetic strategy employed, on the basis of biomimetic concepts, is a useful procedure for the enantiospecific preparation of (+)-vernolepin-related compounds from accessible germacrolides.
Palladium II promoted rearrangement of germacranolides. Synthesis of (+)-stoebenolide and (+)-dehydromelitensin
Barrero, Alejandro F.,Oltra, J. Enrique,Alvarez, Miriam
, p. 1401 - 1404 (2007/10/03)
Catalytic amounts of bis(benzonitrile)palladium (II) chloride enhanced reaction rates of germacranolides Cope rearrangement to elemanolides. On the other hand, equimolecular amounts of the palladium complex transformed germacranolides into eudesmanolides. These phenomena provide a versatile procedure for the synthesis of eudesmanolides and elemanolides under relatively mild experimental conditions. Thus, (+)-stoebenolide and (+)-dehydromelitensin were alternatively synthesized starting out from (+)-salonitenolide.
Studies on the Syntheses of Sesquiterpene Lactones. 8. Syntheses of Saussurea Lactone, 8-Deoxymelitensin, and 11,12-Dehydro-8-deoxymelitensin via a Novel Fragmentation Reaction
Ando, Masayoshi,Tajima, Kiyoshi,Takase, Kahei
, p. 1210 - 1216 (2007/10/02)
Saussurea lactone (4), 8-deoxymelitensin (18), and 11,12-dehydro-8-deoxymelitensin (23) have been synthesized from (11S)-1,1-(ethylenedioxy)eudesm-3-eno-13,6α-lactone (6) in ten steps, seven steps, and nine steps, respectively.The key step involves a nove
