Abstract
A crystalline constituent, futoenone ; C20H20O5, mp 197°, was isolated from Piper futokazura and proved to have the structure (I). The result of regenerating futoenone from the diacetate (Va) via the tosyl-phenol (X), providing an interesting example of Ar1-6 participation, strongly supported the spiro-dienone structure of futoenone. The stereochemistry was also proposed by the data of NMR. The total synthesis of futoenone was accomplished.
