Furanosesquiterpene lactone

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... 

Ricciocarpin A, a furanosesquiterpene lactone, was first isolated from an axenic culture of the European liverwort Ricciocarpos natans in 1990. It bears a <5-... 

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). 

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]. 

---