TRIFLUOROMETHYLATION REACTIONS OF CF3I, TE(CF3)2, SB(CF3)3, HG(CF3)2, AND CD(CF3)2.D WITH FURAN, THIOPHENE, PYRROLE AND PARA-BENZOQUINONE

The trifluoromethylation reactions of Cd(CF3)2·glyme, Hg(CF3)2, Sb(CF3)3, CF3I, and Te(CF3)2 with furan, thiophene, pyrrol, and p-benzoquinone are compared under similar conditions. During the photochemical reactions the reactivity increases in the series Cd(CF3)2·glyme < Hg(CF3)2 < Sb(CF3)3 < CF3I < Te(CF3)2. Cd(Cf3)2 complexes do not react to form trifluormethylated compounds either by photóchemical or by thermal initiation. The best reagents for thermal reactions are CF3I and Te(CF3)2. The yields and the compositions of the products depend on the time of irradiation and on the temperature. The reactions with the heterocyclic compounds mainly yield 2-trifluoromethylfuran, 2-trifluoromethylthiophene, and 2-trifluoromethylpyrrol, respectively. Te(CF3)2 and furan or thiophene additionally give dihydro-trifluoromethylfuran and -thiophene compounds. With p-benzoquinone surprisingly the trifluoromethylhydroquinones are formed. In all reactions Te(CF3)2 is the most suitable trifluoromethylation reagent. The 1H-, 19F-NMR, the i.r. and mass spectra are described. © 1990.