Enantioselective Total Synthesis of Dysidavarone A, a Novel Sesquiterpenoid Quinone from the Marine Sponge Dysidea avara

Dysidavarone A, a structurally unprecedented sesquiterpenoid quinone, was synthesized in 30 % overall yield in a longest liner sequence of 13 steps from commercially available o‐vanillin. A highly strained and bridged eight‐membered carbocyclic core was established by the C7C21 carbon bond formation through a copper enolate mediated Michael addition to the internal quinone ring. The power of a copper enolate! Dysidavarone A, a structurally unprecedented sesquiterpenoid quinone, was synthesized in 30 % overall yield in a longest linear sequence of 13 steps from commercially available o‐vanillin (see scheme; TBS=tert‐butyldimethylsilyl). A highly strained and bridged eight‐membered carbocyclic core was established by the C7C21 carbon bond formation through a copper enolate mediated Michael addition to the internal quinone ring.