SYNTHESIS OF PARTIALLY FLUORINATED HETEROCYCLES FROM 4,4-BIS(TRIFLUOROMETHYL)SUBSTITUTED HETERO-1,3-DIENES VIA C-F BOND ACTIVATION AND THEIR APPLICATION AS TRIFLUORO-METHYL SUBSTITUTED BUILDING BLOCKS

摘要

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.alpha-Trifluoromethyl alpha-amino acids,trifluoromethyl substituted butenolides and alpha-trifluoromethyl-gamma-keto acids are readily available via 5-fluoro-4-trifluoromethyloxazoles and 2-fluoro-3-trifluoromethylfurans,respectively.