Metal-Free Synthesis of 2-Trifluoromethyl Furans

Significance

Reported is a concise, metal-free synthesis of 2-trifluoromethyl furans by the condensation of readily available keto fumarates 1 and keto acrylates 2 with trifluoroacetic anhydride (TFAA). In this reaction, TFAA acts as a simple CF₃ source and the reaction proceeds rapidly at room temperature by mediation of Ph₃P to afford the 2-trifluoromethyl furans 3 or 4 in high yields. Notably, a 40 mmol scale reaction proceeding in 96% yield shows its efficiency and potential on scale-ups. The mechanism for this cascade process is unclear.