Prenylated benzophenone derivatives from Hypericum patulum.

A new prenylated benzophenone, hypatulin C (1), was isolated from the leaves of Hypericum patulum together with a biogenetically related analog, hypelodin B (2). Hypatulin C (1) had a tricyclic [4.3.1.03,7]-decane moiety substituted by four prenyl groups. The structure of 1 was elucidated by detailed spectroscopic analyses, while the absolute stereochemistries of 1 and 2 were assigned by comparison of their ECD spectra with TDDFT calculated spectra.