Unusual Transannular Cyclization Products of Sarcophytoxide, a 14-Membered Marine Cembranoid: Anomalous Stereochemistry of Epoxide−Ketone Rearrangement

Treatment of sarcophytoxide with trimethylsilyl trifluoromethanesulfonate afforded an aromatic ketone as an unusual cyclization product. The
modified Mosher's method and X-ray analysis performed on the aromatic ketone revealed that it is a 4:1 mixture of 8(R)- and 8(S)-enantiomers.
It also suggested that the precursor ketone has 8(R)-configuration, which is contradictory to that expected from the ordinary epoxide−ketone
rearrangement.