Study towards bioactive pyrone derivatives from the marine red alga Phacelocarpus labillardieri

Red algae of the genus Phacelocarpus labillardieri produce a structurally rather unique class of macrocyclic pyrone derivatives with phospholipase A₂ inhibiting properties and potential neuromuscular blocking activity. They were also shown to be potent feeding inhibitors for various marine herbivorous gastropods. Described herein is the first preparative study towards these conspicuous secondary metabolites. Their carbon skeleton has been assembled in a few straightforward steps using ring closing alkyne metathesis (RCAM) catalyzed by the Schrock alkylidyne complex (tBuO)₃WCCMe₃ to forge the meta-cyclophane core with high efficiency.