Absolute Configuration of Symbiodinolactone A.

The absolute configurations at five stereogenic centers in symbiodinolactone A, a 12-membered macrolide isolated from the symbiotic marine dinoflagellate Symbiodinium sp. associated with an acoelomorpha Amphiscolops sp., were determined to be 7R,11R,12R,13R,14R. A combination of different techniques was applied in this regard such as Rychnovsky's method, Kishi's universal NMR databases, the modified Mosher's method, and comparison of the NMR data of the bis(S)-MTPA ester of a degradation product of symbiodinolactone A with those of synthesized reference compounds. In addition, symbiodinolactone A was found to exhibit cytotoxicity against L1210 murine leukemia cells.