The otteliones A (1) and B (2),[1–3] are exceptionally potent anticancer agents that inhibit the growth of a wide range of tumor cell lines with in vitro GI50 values of less than 100 pm for 1 and less than 1 nm for 2.[1] For example, total growth inhibition was observed against one breast cancer cell line and one CNS cancer cell line in the nm to pm range.[1] Additionally, it has been established that ottelione A inhibits tubulin polymerization.[3] Both compounds ...