Reaction of 2-fluoroaziridines with potassium alkynyltrifluoroborates in the presence of BF3·OEt2 leads to fluorinated propargyl amines in moderate to good yields. The reaction proceeds as an in situ isomerization of 2-fluoroaziridines to α-fluorinated imines, followed by the reaction of the imine with alkynyldifluoroborane, which is generated in situ from the potassium alkynyltrifluoroborates and BF3·OEt2. © 2007 Elsevier Ltd. All rights reserved.