Synthesis of Ophiocerin C

Recently, Gloer group isolated several natural products from the solid-substrate fermentation cultures of fresh water fungi O. venezuelense.1 Investigation of the ethyl acetate-extract exhibiting modest activity against Candida ablicans led to the isolation of the compounds containing the tetrahydropyran core as shown in the following (Figure 1). Because there exist numerous biologically active natural products that have the substituted tetrahydropyrans and related structures,2,3 we decided to study the synthesis of these ophiocerins. The first and only total synthesis of ophiocerin B and C has been reported by Yadav group.4 They utilized the Sharpless asymmetric dihydroxylation as a key reaction to establish the diol stereochemistry. We have been intrigued in ophiocerins due to the interest-ing array of substituents on the tetrahydropyran ring. Syn