Synthesis and comparison of N-fluorobis[(perfluoroalkyl)sulfonyl]imides with different perfluoroalkyl groups

N-fluorobis[(perfluoroalkyl)sulfonyl]imides, CF3SO2N(F)SO2Rf (Rf′=C4F9, C6F13, C8F17) and (C4F9SO2)2NF, were prepared by direct fluorination of corresponding N–H compounds using elemental fluorine without a solvent in good to excellent yields. All of these N–F compounds are electrophilic fluorination agents and can easily deliver “F+” to certain molecules. Their reactions with aromatic rings, beta-diketones, and alkenes were investigated to compare their fluorination power.