The Asteraceae is characterized by structurally diverse sesquiterpene lactones and furanosesquiterpenes. In this review the tribal, subtribal and generic distribution of sesquiterpene lactones is examined and the compounds’ utility as taxonomic characters discussed. Sesquiterpene lactones fulfill the major requirements for good analytic and synthetic characters. Studies of infraspecific sesquiterpene lactone variation indicate that different elements within complex taxa are often defined by distinct chemistries, termed chemotypes. Chemotypes have been identified within many of the thoroughly investigated taxa:Ambrosia camphorata, A. chamissonis, A. confertiflora, theA. cumanensis-A. psilostachya-A. artemisiifolia complex,A. dumosa, Artemisia tridentata, Gaillardia pulchella andMelampodium leucanthum. Such an analytic usage is mostly restricted to the infraspecific level. Synthetic usage at the interspecific level and above profits from the application of a biogenetically based methodology for sorting out the complex molecules’ carbon-skeletal and substitutional features into unit characters. Cladistics or Hennigian phylogenetic systematics provides a useful framework for such an analysis. Preliminary surveys indicate that sesquiterpene lactones are especially good characters for differentiating subtribes within several major tribes: the Vernonieae, Heliantheae and Mutisieae. As yet, too few data are available for other tribes to discern such patterns. Species surveys inVernonia, Ambrosia, Iva, Parthenium,Tetragonotheca andArtemisia demonstrate that sesquiterpene lactones are useful in discerning infrageneric groups. The biogenetic cladistic analysis of the interspecific sesquiterpene lactone variation inIva shows the efficacy of this analytical methodology. At present, such biogenetically based approaches are impeded by limited biosynthetic evidence and the erratic distribution of sesquiterpene lactones within the family. Instances of apparent displacement of sesquiterpene lactones by other terpenoids (i.e. sesquiterpene furans, alcohols and acids, diterpenes, diterpene acids, etc.) at various taxonomic levels suggest that ultimately sesquiterpene lactones must be interpreted as taxonomic characters in the context of the family’s total terpene chemistry. All taxa from which sesquiterpene lactones have been reported are listed together with the compound names, major structural features and the literature cited. A less-complete listing is provided for taxa producing furanosesquiterpenes. Structures for all reported compounds are included. Two appendices listing alphabetically taxa and compounds and relevant text page numbers permit cross-indexing of plants and compounds.

Sesquiterpene lactones as taxonomic characters in the asteraceae

Chromenes and benzofurans of the asteraceae, their chemistry and biological significance

Acetylenes and related compounds in anthemideae

Three cadinene derivatives and a prostaglandin-like acid from Chromolaena species

Cis-Kolaveninsäure und weitere inhaltsstoffe aus vertretern der tribus eupatorieae☆

Notiz über ein neues Germacranolid aus Chromolaena glaberrima (DC) K. et R.

A labdane derivative from Chromolaena collina and a p-hydroxyacetophenone derivative. From Stomatanthes corumbensis

Neue nerolidol-derivate aus Ageratina aschenbornia☆

Ausgehend von 5-Methyl-2-cyclohexen-1-on (1) werden uber das Zwischenprodukt 4 die Cyclopentancarbaldehyde 5 und 6 synthetisiert. Wittig-Reaktion fuhrt zu den epimeren Nitrilen 7 und 8, die nach Uberfuhrung in die Aldehyde 9 und 10 durch Reaktion mit β-Furyllithium die Carbinole 11 und 12 liefern. Mangandioxid-Oxidation gibt die Ketone 13 und 14, deren spektroskopischen Daten mit denen der Naturstoffe ubereinstimmen.



Naturally Occuring Terpene Derivatives, 3061) Synthesis of a Furan Sesquiterpene from Eumorphia prostata



Starting with 5-methyl-2-cyclohexen-1-one (1) through the intermediate 4 the cyclopentene carbaldyhydes 5 und 6 were synthesized. Wittig reaction led to the epimeric nitriles 7 und 8, which after conversion to the aldehydes 9 and 10 on reaction with β-furyllithium afforded the carbinols 11 and 12. Manganese dioxide oxidation yielded the ketones 13 and 14, their spectral data being in agreement with those of the natural compounds.

Lothar Fiedler

Papers

Cis-Kolaveninsäure und weitere inhaltsstoffe aus vertretern der tribus eupatorieae☆

Notiz über ein neues Germacranolid aus Chromolaena glaberrima (DC) K. et R.

A labdane derivative from Chromolaena collina and a p-hydroxyacetophenone derivative. From Stomatanthes corumbensis

Neue nerolidol-derivate aus Ageratina aschenbornia☆

Natürlich vorkommende Terpen‐Derivate, 3061) Synthese eines Furansesquiterpens aus Eumorphia prostata