Jaspolides G and H, unique bisisomalabaricanes from the Chinese marine sponge Jaspis sp.

Two unique bisisomalabaricanes jaspolides G (1) and H (2) were isolated from the marine sponge Jaspis sp. Their structures were elucidated on the basis of extensive spectroscopic data (IR, MS, and 1D and 2D NMR) analyses. A possible biogenetic pathway via Diels–Alder dimerization for jaspolides G and H was also proposed.