FLUORINATED ACETYLENES. PART 7. PREPARATION AND SOME REACTIONS OF 4,4,4-TRIFLUOROBUT-2-YNOIC ACID AND 1-PHENYL-4,4,4-TRIFLUOROBUT-2-YN-1-OL

Article abstract of DOI:10.1016/S0022-1139(00)80446-7

Treatment of the salt CF3C CLi with alkyl chloroformates affords the compounds CF3C CCO2R (R=Et and CH2Ph) in relatively low yield and with gaseous carbon dioxide yields the acid CF3C CCO2H.Reaction of the acid with diazomethane gives the methyl ester which, with an excess of the reagent, undergoes regiospecific 1,3-dipolar cycloaddition to produce 3-carbomethoxy-4-trifluoromethylpyrazole and hence the 3- and 5-carbomethoxy-1-methyl-4-trifluoromethylpyrazoles.Oxidation of the alcohol CF3C CCH(OH)Ph (active MnO2) affords a 70:23 mixture of 3-benzoyl-2,4-bis(trifluoromethyl)-2-hydroxy-6-phenyl-α-pyran and E-1,3-dibenzoyl-2-trifluoromethylpropene (via the ketone CF3C CCOPh).