Aggreganoids A–F, Carbon-Bridged Sesquiterpenoid Dimers and Trimers from <i>Lindera aggregata</i>

Abstract

Six oligomeric sesquiterpenoids, aggreganoids A-F (<b>1</b>-<b>6</b>), were isolated from <i>Lindera aggregata</i>. Aggreganoid A (<b>1</b>) and B (<b>2</b>) are two unprecedented methine- or methylene-bridged sesquiterpenoid trimers possessing a unique C₄₆ skeleton. Aggreganoids C-F (<b>3</b>-<b>6</b>) are the first examples of carbon-bridged disesquiterpenoids with a C₃₃ or C₃₁ 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.