AbstractThe polymerization of 1,1,1‐trifluoroacetone with aliphatic secondary amines is reported. The polymerization product is found to be a mixture of four diastereoisomers of the cyclic trimer, the structure of which has been determined using proton and fluorine magnetic resonance spectroscopy. The proportions of the isomers have been estimated to be 70:19:8:3 from the19F resonance spectrum. A comparative study of the reaction products of trifluoroacetone with metallic sodium and diethylamine is also discusse