A Short, Scalable Synthesis of the Carbocyclic Core of the Anti-Angiogenic Cortistatins from (+)-Estrone by B-Ring Expansion

A rapid and scalable synthesis of the carbocyclic core of the potent antiangiogenic natural products, the cortistatins, is presented starting from readily available (+)-estrone. Key steps include a regio- and stereoselective benzylic cyanation and a Demjanov rearrangement.