HFO-1234yf as a CF3-building block: Synthesis of trifluoromethyl-benzophenone derivatives by deoxygenative aromatisation

Trifluoromethyl ynones derived from the 4th generation refrigerant 2,3,3,3-tetrafluoropropene (HFO-1234yf) undergo rapid Diels-Alder cycloaddition reactions with furans in near quantitative yields. Subsequent deoxygenation of resulting oxabicyclic adducts leads to formation ortho-trifluoromethylbenzophenones generally good yields without need for purification by column chromatography. Complete selectivity a single regioisomer was observed all cases. This method provides new route an inexpensive feedstock highly substituted CF3-aromatic systems that can be difficult access selectively established methods.