Total synthesis of euplectin, a natural product with a chromone fused indenone.

The first total synthesis of euplectin, a rare metabolite with a chromone annulated indenone motif, has been accomplished in 17 steps. This has been possible through interplay among three key reactions: a Hauser sulfoxide annulation, a new chromone formation and a late-stage retro-Diels-Alder reaction. The entire regiochemical integrity of the successful route is established by an iodine-catalyzed aromatization of a cyclohexane-1,3-dione and the Hauser annulation.