Synthetic Studies on Presporolide, a Putative Enediyne Precursor of Sporolides.

A synthesis of the core framework of presporolide, which possesses both a strained bicyclo[7.3.0]dodecadiyne moiety and a distinctive macrolactone structure, is reported. This synthesis features: (i) a Cu-mediated O-arylation of a hindered tertiary alcohol using triarylbismuth reagent; (ii) stereoselective construction of the strained nine-membered diyne ring; and (iii) atroposelective formation of the macrolactone.