Synthesis of partially fluorinated heterocycles from 4,4-bis(trifluoromethyl) substituted hetero-1,3-dienes via C-F bond activation and their application as trifluoromethyl substituted building blocks

Bis(trifluoromethyl) substituted hetero-1,3-dienes can be transformed into partially fluorinated five-membered heterocycles by a new reductive cyclization protocol. Certain members of the new class of heterocycles represent versatile building blocks. α-Trifluoromethyl a-amino acids, trifluoromethyl substituted butenolides and a-trifluoromethyl-y-keto acids are readily available via 5-fluoro-4-trifluoromethyloxazoles and 2-fluoro-3-trifluoromethylfurans, respectively.