A new and effective route to (±)-botryodiplodin and (±)-epi-botryodiplodin acetates using a halogen atom transfer Ueno-Stork cyclization

(±)-Botryodiplodin and (±)-epi-botryodiplodin acetates were prepared in good yields following a practical four step route. The method, for the construction of the strategic tetrahydrofuran ring, hinged on an unprecedented halogen atom transfer Ueno-Stork cyclization of an O-allyl α,α-dihalohemiacetal acetate, catalyzed by the redox complex CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine.