Furanosesquiterpenes

The difference in reactivity is perfectly revealed in Metz s total synthesis of the molluscicidal furanosesquiterpene lactones ricciocarpin A (50) and B (51) (Scheme 9) [32]. Attempts to convert acrylate 43 to lactone 44 using Grubbs5 catalyst A or Schrock s molybdenum catalyst B resulted in very low yields of the... 

Among the characteristic furanosesquiterpenes of myrrh trapped by headspace SPME, curzerene (65) (= isofuranogermacrene), furanoeudesma-1,3-diene (80) and lindestrene... 

Searle, P.A. Jamal, N.M. Lee, G.M. Molinsky, T.F. (1994A) Configurational analysis of new furanosesquiterpenes from Dysidea herbacea. Tetrahedron, 50, 3879-88. 

Thiofurodysinin (326), a furanosesquiterpene from Dysidea avara from Australia, was the first report of a sesquiterpene mercaptan from a sponge [296]. 

A synthesis of the furanoeremophilane ( )-ligularone has been accomplished via the intramolecular Diels-Alder reaction of an oxazole with an alkynic dienophile (81JA4611). The lactone (359) was treated with lithium methylisocyanide to yield the oxazole (360). Oxidation of alcohol to aldehyde and reaction of this unstable aldehyde with lithiopropyne gave a 55 45 mixture of diastereomeric alcohols (361). Oxidation of the mixture gave a single alkynic ketone (362) which when refluxed in ethylbenzene afforded the desired furanosesquiterpene (363 Scheme 78). 

A total synthesis of ( )-dihydrospiniferin-l (149), an unstable furanosesquiterpene from the Mediterranean sponge Pleraplysilla spinifera, has been reported. It is of interest because (149) is the first reported natural product incorporating the novel l,6-methano[10]annulene carbon framework (80JA4274). The key step in the synthesis is the condensation of the aldehyde (150) with methoxymethylenetriphenylphosphorane in toluene to give the bis-enol ether (151). Treatment of (151) with aqueous hydrochloric acid in diethyl ether affords the furan (149). 

Furanosesquiterpene -food toxicant [FOOD TOXICANTS, NATURALLY OCCURRING] (Vol 11)... 

Wittig-Homer reactions.3 The reaction of the phosphonate 2 with the aldehyde 1 under literature conditions gives the fraras-stilbene 3 in only about 10% yield. Addition of 15-crown-5 raises the yield to 45%. This step was used in a synthesis of pallescensin E (4), a furanosesquiterpene in a marine sponge. 

Furanosesquiterpenes.1 The furanosesquiterpene petasalbine (1) has been synthesized by application of bis heteroannelation (equation I). 

M4604>. The synthesis of a fullerene embedded with a furan motif was reported, which was confirmed by a single crystal X-ray analysis <07OL1741>. Tandem Wittig reaction-intramolecular Diels-Alder cycloaddition of 2-furfural provided tricyclic furans, which may serve as precursors in the synthesis of furanosesquiterpenes <07TL3517>. 

A furoannulation protocol via dichlorocarbene adducts of alkyl enol ethers has been applied to the synthesis of the furanosesquiterpene pallescensin A (Equation 39) <2006TL6817>. 

Application of this rearrangement provides a short synthesis of the furanosesquiterpene myodesmone (1). 

Sponges produce furanosesquiterpenes of various skeletal types, such as furodysinin (118) from Dysidea herbacea and nakafuran-8 (119) from D. etheria, the latter of which is antifeeding. Similarly, mixed shikrmate-mevalonate metabolites are often encountered as sponge metabolites the first example is avarol (120), which was isolated from Dysidea avara. Several related compounds have been isolated from dictyoceratid... 

Two unique ring enlargements which can also be classified as divinyl-cyclopropane-cycloheptadiene expansions are shown in equations 177 and 178 ". The last reaction has been employed for constructing the l,6-methano[10]annulene carbon skeleton required for the unusual furanosesquiterpene dihydrospiniferin-1. ... 

Attempted formation of the bromide from the furanosesquiterpene 18.10 with Ph3P and CBr4 gave furanether A (18.5) and pyrovellerofuran (18.3), as main products (93). The latter compound had previously been obtained by thermal rearrangement of isovelleral (6.1) (90), while furanol 18.10, isolated from L. vellereus (93), was also formed when velutinal derivatives were decomposed on silica gel (85). This experiment correlated the absolute configuration of isovelleral (6.1) with that of velutinal esters and, indirectly, with the stereostructures of many other Lactarius... 

Marine sponges of the genus Dysidea are a rich source of structurally unique and biologically active compounds, including spiro-sesquiterpenes such as spirodysin and dehydroherbadysinolide, furanosesquiterpenes based on the furodysinin and furodysin skeletons, brominated diphenyl ethers, polychlorinated alkaloids and other compounds [99-103],... 

New Zealand liverwort Schistochila glaucescens produced three known bisbibenzyls, viz neomarchantins A and B, and marchantin C (813), with two unprecedented sesquiterpenes bisbibenzyls Glaucescens Bis Bibenzyl (GBB) A and (GBB) B (295 and 296), the first examples of a bisbibenzyl having a sesquiterpene moiety. A biosynthetic route to sesquiterpene lactone glaucescenolide, GBB A and GBB B (295 and 296), via a shared furanosesquiterpene intermediate, is proposed [148]. 

The enantioselective construction of the furanosesquiterpene (+)-pallescensin has been achieved by the reaction sequence 32 - 371087. 

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