Synthesis of the FGHI Ring System of Azaspiracid We thank Dr. D. H. Huang and Dr. G. Siuzdak for NMR spectroscopic and mass spectrometric assistance, respectively. Financial support for this work was provided by The Skaggs Institute for Chemical Biology, the National Institutes of Health (USA), a predoctoral fellowship from Bristol-Myers Squibb (F.B.), postdoctoral fellowships from the Academy of Finland, the Ella and Georg Ehrnrooth Foundation, and the Tauno Tönning Foundation (all to P.M.P.), ArrayBiopharma (N.Z.), and Bayer AG (N.D.), and grants from Abbott, Amgen, ArrayBiopharma, Boehringer-Ingelheim, Glaxo, Hoffmann-LaRoche, DuPont, Merck, Novartis, Pfizer, and Schering Plough.