Lignans, like podophyllotoxin, have cancer-fighting properties and are used in chemotherapy. An efficient and highly modular approach for the synthesis of lignan natural products has been developed, culminating in several total syntheses, including that of podophyllotoxin. The approach involves a late stage domino radical reaction. Our strategy has several advantages over previous syntheses, the most significant being that it allows a high level of convergency at the end of the synthetic route.
We have developed a novel, efficient and very general way to produce complex polycyclic structures from simple, unsaturated, acyclic precursors using sequences of Diels–Alder reactions. Applications of these processes in total synthesis are being investigated. In 2007 we completed the shortest total synthesis of the natural product triptolide, which shows great potential in medicine due to its myriad biological activities.
Significant progress has also been made towards the natural product viridin, a particularly challenging structure that we have been targeting since 2003.