Cuparene‐Derived Sesquiterpenes from the Chinese Red Alga Laurencia okamurai Y amada

Four new cuparene‐derived sesquiterpenes, laureperoxide ( 1 ), 10‐bromoisoaplysin ( 2 ), isodebromolaurinterol ( 3 ), and 10‐hydroxyisolaurene ( 4 ), together with seven known, related sesquiterpenes, 5 – 11 , have been isolated from the red alga Laurencia okamurai. Their structures were determined on the basis of detailed spectroscopic analyses and comparison with known compounds. Compounds 8 – 11 were shown for the first time to represent true natural products, and the full 1 H‐ and 13 C‐NMR assignments of 5 are reported for the first time.