Synthesis of 1,1,1,7,7,7-hexafluoroheptane-2,4,6-trione, the simplest fluorinated 1,3,5-triketone

A simple, convenient and effective method to synthesize 1,1,1,7,7,7-hexafluoroheptane-2,4,6-trione, the simplest fluorinated 1,3,5-triketone, on a preparative scale was developed. The title compound was obtained by a Claisen-type double condensation of acetone with trifluoroacetic acid ethyl ester and isolated as a solid monohydrate from the reaction mixture. Subsequent dehydration proceeds smoothly to produce the desired compound as an individual substance. Its peculiar tautomeric (keto–enol, ring–chain) features in various solvents are discussed.