Y. Zhao et al., LIGULAVERIN-A, A STRUCTURALLY NOVEL SESQUITERPENOID-DERIVED METABOLITE POSSIBLY FORMED VIA A BIOLOGICAL DIELS-ALDER REACTION, Chemical communications, (21), 1996, pp. 2473-2474
The crystal structure of Ligulaverin A 1, isolated from Ligularia veit
chiana (Hemsl,) Greenm,, reveals a novel carbocyclic skeleton which is
likely to be derived from a hydroxymethacrylate ester of an eremophil
ane sesquiterpenoid via an intramolecular Diels-Alder reaction.