Halogenated Sesquiterpenes from the Marine Red Alga Laurencia saitoi (Rhodomelaceae)

Four new halogenated sesquiterpenes, 10‐bromo‐3‐chloro‐2,7‐epoxychamigr‐9‐en‐8α‐ol (1), 2,10β‐dibromochamigra‐2,7‐dien‐9α‐ol (2), (9S)‐2‐bromo‐3‐chloro‐6,9‐epoxybisabola‐7(14),10‐diene (3), and (9R)‐2‐bromo‐3‐chloro‐6,9‐epoxybisabola‐7(14),10‐diene (4), were characterized from the marine red alga Laurencia saitoi. In addition, two known halosesquiterpenes, 2,10‐dibromo‐3‐chlorochamigr‐7‐en‐9α‐ol (5) and isolaurenisol (6), were also isolated and identified. Their structures were established on the basis of extensive analysis of spectroscopic data.