Synthesis of a Liphagal–Frondosin C Hybrid and Speculation on the Biosynthesis of the Frondosins

A hypothesis for the biosynthesis of the frondosins A–E is presented. Synthesis of a liphagal–frondosin C hybrid molecule has been achieved, with the frondosin C 6–7–5–6 ring system being constructed by a photochemical process that follows an intramolecular Paternò–Büchi reaction/fragmentation pathway.