Due to the low stability of sulfonyl chlorides 141 under reducing conditions, they were transformed into the sulfonyl fluorides 136 by reaction with KHF2 in MeOH-H2O (1:1, v/v) at rt, and the corresponding SO2F-substituted derivatives were synthesized in 72-94% yield (85% average). The key step involved the reduction of the nitrile group of SO2F-substituted (hetero)cycloalkanecarbonitrile 136 with NaBH4 in the presence of NiCl2•6H2O at -20°C. Remarkably, the iminoalkylsulfonyl fluorides formed initially underwent intramolecular sulfonylation and reduction, leading to the formation of the spirocyclic γsultams 146 in 61-84% yield after additional chromatographic purification (Scheme 22). Notably, even in the presence of Boc2O, cyclization exclusively occurred to give sultams, while the formation of the corresponding aminoalkylsulfonyl fluorides 147 was not observed under the given synthesis conditions. Scheme 22. Reductive sulfonylation for the synthesis of γsultams 146