Revision of the Stereochemistry of Elisabethatriene, a Putative Biosynthetic Intermediate of Pseudopterosins

In the past, we have questioned the accuracy of the stereochemistry of elisabethatriene, a putative biosynthetic intermediate of pseudopterosins, in light of the configuration of elisabethatrienol isolated from Pseudopterogorgia elisabethae, which was represented as 1S,4R,9S,11S. We have reinvestigated the stereochemistry of elisabethatriene. Elisabethatriene with the reported 1S,4R,9R,11S configuration was synthesized starting from (-)-isopulegol in its enantiomeric form. The H-1- and C-13-NMR data of the synthesized compound differed from those reported for elisabethatriene. In addition to the fact that elisabethatriene is converted into pseudopterosins, this finding has allowed us to propose that elisabethatriene should have the 1S,4R,9S,11S stereochemistry, which is identical to that of elisabethatrienol.