Acetylene cobalt complex and vinylsilane strategy in the synthesis of ciguatoxin (D)EF analog

A synthetic route to the (D)EF analog of ciguatoxin has been explored through acetylene cobalt complex and vinylsilane strategy. The central reactions in the synthesis are: (i) ether ring formation mediated by acetylene cobalt complex and (ii) decomplexation of the endo-acetylene cobalt complexes to vinylsilanes or olefins. Unusual rearrangement of epoxy-silane to allylic alcohol is also described.