Synthesis and structural revision of calafianin, a member of the spiroisoxazole family isolated from the marine sponge, Aplysina gerardogreeni

Calafianin 1 was successfully synthesized by employing a spiroisoxazoline compound, which was produced by electrochemical oxidation of the oximino-phenol derivative 7 followed by reduction. This investigation revealed a structural revision of 1, the trans-relationship of two oxygen atoms between the epoxide and the isoxazoline.