Tetrahydroxy 10-Membered Cyclic Enediynes

The preparation of cyclic 10-membered tetrahydroxy enediynes is reported. The synthesis starts
from tartaric acid and allows the control of the relative stereochemistry. Acetal protection of the
2,3-hydroxy groups stabilizes the enediyne during synthesis. Removal of the cyclic protecting group
with EtSH/TFA transforms the stable compounds into reactive enediynes, and the rate constants
of their cyclization were determined in benzene and water. The cytoxicity of the activated compounds
was assayed against tumor cells in vitro, but the growth inhibitory effect was weak compared to
cisplatin.