Panamonon A and B, a pair of novel tetrahydrobenzofuran derivatives from Litsea panamonja (Nees) Hook. f.

► A pair of novel tetrahydrobenzofuran derivatives with a unique C18 carbon skeleton was isolated. ► The new compounds possess an unprecedented C18 carbon skeleton and are designated as “panamonane”. ► They are featured with a tetrahydrobenzofuran-2,5(3H,6H)-dione moiety and a geranyl side chain. ► The plausible biosynthetic pathways of them were discussed.