Concise synthesis of (±)-horsfiline and (±)-coerulescine by tandem cyclisation of iodoaryl alkenyl azides

A brief, efficient and economical synthesis of the spiropyrrolidinyloxindoles, horsfiline and coerulescine, has been achieved, starting from itaconic acid and, respectively, p-anisidine or o-iodoaniline. Tandem radical cyclisation of iodoaryl alkenyl azides is the key step in both syntheses.