We have developed efficient synthetic routes to heterocyclic ring systems using transition metals (palladium, iron, and silver). Recent applications of this chemistry to the total synthesis of biologically active alkaloids include carbazole alkaloids (pityriazole, euchrestifoline, the antiostatins), crispine A, pentabromo- and pentachloropseudilin. The two latter alkaloids represent a novel class of myosin ATPase inhibitors that led to the discovery of a new allosteric binding site of the protein.