Cordybislactone, a stereoisomer of the 14-membered bislactone clonostachydiol, from the hopper pathogenic fungus Cordyceps sp. BCC 49294: revision of the absolute configuration of clonostachydiol.

Cordybislactone (3), a new stereoisomer of the 14-membered bislactone clonostachydiol, together with its open ring analog (4), was isolated from the hopper pathogenic fungus Cordyceps sp. BCC 49294. The relative and absolute configurations of 3 were determined by chemical derivatizations, including the modified Mosher's method. The stereochemistry of clonostachydiol was determined using the natural compound isolated from Xylaria sp. BCC 4297. The result revealed that the absolute configuration of clonostachydiol, previously determined by synthesis, should be revised to its enantiomer.