Total Synthesis of Lucidumone: Attempted Shortcuts, Dead Ends and Lessons Learnt

Abstract Lucidumone is a meroterpenoid isolated from the mushroom Ganoderma lucidum, displaying selective COX-2 inhibitory activity. In this work, we detail our synthetic efforts which led to the first enantioselective synthesis of lucidumone in 13 steps (longest linear sequence). Beyond the key retro-[4+2]/intramolecular Diels–Alder cascade, we discuss the difficulties regarding fragment assembly, introduction of the methyl ketone moiety and choice of adequate protecting group.