An efficient preparation of β-amino-α,α-difluoroketones 4 was developed. Reactions of 1,1-difluorovinylmethylethers 1 with N-acyliminiumintermediates, generated by treating biscarbamates 2 with trifluoromethanesulfonic anhydride (Tf2O) in the presence of molecular sieves 4A (MS 4A), provided 4 in good yields.