Total Synthesis of (±)-Phaeocaulisin D.

The tropone sesquiterpene phaeocaulisin D, isolated from the rhizomes of Curcuma phaeocaulis, has previously been shown to inhibit nitric oxide production in macrophages. A total synthesis of phaeocaulisin D was accomplished by using an intramolecular cyclization-dearomatization as a key step. The highlights of the synthesis are effective formation of the 5-7 fused tropone system, and selective methylation of a late-stage intermediate.