Novel Synthesis of Methylenecyclobutanols and 4-Methylenetetrahydrofurans from γ-Oxide Ylides

The reaction of δ-halo-γ-oxide ylide, prepared from methylenetriphenylphosphorane and epichlorohydrin, with aldehydes afforded alkylidenecyclobutanols in moderate yields. The reaction initially proceeded through internal nucleophilic attack on δ-carbon of this ylide. Another novel approach toward the synthesis of 4-methylenetetrahydrofurans was achieved by the reaction of γ-oxide ylides with paraformaldehyde.