Total Synthesis of Dactylicapnosines A and B.

Dactylicapnosines A and B, two natural products from , exhibited potent anti-inflammatory and analgesic activities both in vitro and in vivo. In this paper, we report our second-generation synthesis of dactylicapnosine A and the first total synthesis of dactylicapnosine B. Our synthetic route features acid-induced isomerization of -quinone (), Co-mediated regioselective ring contraction of -quinone (), and oxidative methoxylation of enone (). This modified sequence provides dactylicapnosine A in 14 steps with an overall yield of 12% from a known compound () and also offers opportunities to synthesize dactylicapnosine-like analogues for biological investigations.