Studies toward the AB ring system of the tetrapetalone natural products.

Synthetic efforts toward the rapid assembly of the AB ring system of the tetrapetalones is described. Key to this work was the use of [3+2] cycloaddition/oxidative extrusion methodology to furnish functionalized aryl enones. The Nazarov cyclization of these substrates was examined, and optimized to generate the AB ring carbon skeleton. Then, Pd-catalyzed cross-coupling were conducted, and conditions were identified that enabled installation of the requisite C14-N bond.