Aggreganoids A-F, Carbon-Bridged Sesquiterpenoid Dimers and Trimers from .

Six oligomeric sesquiterpenoids, aggreganoids A-F (-), were isolated from . Aggreganoid A () and B () are two unprecedented methine- or methylene-bridged sesquiterpenoid trimers possessing a unique C skeleton. Aggreganoids C-F (-) are the first examples of carbon-bridged disesquiterpenoids with a C or C skeleton in the plant kingdom. Their structures and absolute configurations were elucidated by using spectroscopic methods and electronic circular dichroism calculations. A plausible biosynthetic pathway of these compounds was also proposed.