Synthesis of new trifluoromethylated furans, dihydrofurans and butenolides starting from gamma-ketothioesters and diisopropylamine

gamma-Ketothioesters were easily transformed into furans, dihydrofurans or butenolides by simple treatment with diisopropylamine in diethyl ether. The Substitution pattern of the starting material has a great influence on the outcome of the reaction. Possible mechanisms for the formation of the heterocycles were proposed. The Structures of all new Compounds were ascribed Using usual NMR data (F-19, H-1, C-13 NMR), X-ray diffraction analysis and H-1-H-1 NOE experiments.