A Facile Approach to 2-CF3-Substituted Seven-membered Oxacycles via Stereoselective Preparation and Cope Rearrangement of 2-CF3-cis-2,3-Bis(alkenyl)oxiranes

Stereoselective preparation and Cope rearrangement of 2-CF3-substituted cis-2,3-bis(alkenyl)oxiranes provides a convenient route to a diverse of 2-CF3-4,5-dihydrooxepins. The reaction sequence followed by reduction or oxidation provides 2-CF3-substituted oxepanes or oxepins, respectively.