Ciereszkolide: Isolation and Structure Characterization of a Novel Rearranged Cembrane from the Caribbean Sea Plume Pseudopterogorgia kallos

An investigation of the chloroform extract of a Colombian specimen of Pseudopterogorgia kallos has led to the isolation of a novel rearranged cembrane, ciereszkolide ( 1 ). The structure of 1 is based on a new carbon skeleton that possesses several unusual structural features, namely, two butyrolactones [one 2(3 H )‐ and one 2(5 H )‐furanone] across a 13‐membered macrocycle, a ( Z )‐trisubstituted olefin, and a five‐membered trans ‐fused cyclic ketal. The structure of 1 was resolved by interpretation of 1D and 2D NMR spectroscopic data supported by HRFAB‐MS, IR, UV, and a single‐crystal X‐ray diffraction analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)