Diastereoselective formation of 2-fluoro-2-trifluoromethyl-3,4-alkadienamides from propargyl alcohols and hexafluoropropene–diethylamine adduct (PPDA)

Treatment of propargyl alcohols (1) with hexafluoropropene–diethylamine adduct (PPDA) affords N,N-diethyl-2-fluoro-2-trifluoromethyl-3,4-alkadienamides (2) that are produced by the Claisen rearrangement of intermediary 2-alkynyl 1-(N,N-diethylamino)-2,3,3,3-tetrafluoro-1-propenyl ethers. Starting from propargyl alcohols bearing a triple bond at the terminal position, the corresponding products (2) were formed with a high stereoselectivity.