A New Cembranoid Diterpene and Other Related Metabolites from the South‐China‐Sea Soft Coral Lobophytum crassum

A new hydroperoxy‐substituted cembranoid diterpene, 2‐hydroperoxysarcophine (= (1a R* ,4 E ,11 E ,14a R *)‐2,3,6,7,10a,13,14,14a‐octahydro‐10a‐hydroperoxy‐1a,5,8,12‐tetramethyloxireno[9,10]cyclotetradeca[1,2‐ b ]furan‐9(1a H )‐one; 1 ), was isolated from the marine soft coral Lobophytum crassum. Also isolated were two other cembranoid diterpenes, obtained for the first time from a natural source, i.e. , 7 β ,8 β ‐epoxy‐4 α ‐hydroxycembra‐1(15),2,11‐trien‐16,2‐olide ( 2 ) and 7 β ,8 β ‐epoxy‐4 β ‐hydroxycembra‐1(15),2,11‐trien‐16,2‐olide ( 3 ), along with three further cembranoid derivatives, five sterols, and two open‐chain metabolites. Their structures and relative configurations were elucidated on the basis of extensive spectroscopic analyses including 1D‐ and 2D‐NMR, and HR‐ESI‐MS experiments.