General Approach to Epipolythiodiketopiperazine Alkaloids: Total Synthesis of (+)-Chaetocins A and C and (+)-12,12′-Dideoxychetracin A

A highly stereoselective and systematic strategy for the introduction of polysulfides in the synthesis of epipolythiodiketopiperazines is described. We report the first total synthesis of dimeric epitri- and epitetrathiodiketopiperazines.