The reaction of 2-acylamino-4,5-dihydro-3-furancarbonitriles 1 with sodiumiodide in N,N-dimethyl-formamide gave the corresponding 1-acyl-2-oxo-3-pyrrolidinecarbonitriles 2 in good yields. Successive treatment of 1 with titanium(IV) chloride and potassium carbonate resulted in the formation of N-acyl-1-cyanocyclopropanecarboxamides 4. The same compounds 2 were also obtained by treatment of 4 with sodium