Synthesis of Dihydroplakortin, 6-epi-Dihydroplakortin, and Their C10-Desethyl Analogues

The first synthesis of the marine endoperoxide 9,10-dihydroplakortin, of its C10-desethyl analogue, and of their corresponding C6 epimers is described. Stereogenic centers at C4 and at the lateral chain have been stereoselectively synthesized through Evans’ chiral auxiliary chemistry. Moreover, the reported synthesis features a one-pot three-step hydroperoxysilylation/cyclization reaction for the construction of the endoperoxide ring system. Homologation of the aldehyde resulting from diol cleavage through a Wittig-based strategy gave access to the ester-containing lateral chain at C3.