N-Alkylsulfonamide Nucleophilicity: Experimental and Computational Assessment of Nitrogen Nucleophilicity of (S)-2-(Iodomethyl)-1-tosylpyrrolidine.

Sulfonamides are generally considered to be non-nucleophilic due to the presence of a sulfonyl group. We show that N-alkylsulfonamides are sufficiently basic/nucleophilic to be protonated and react with electrophilic centers. Contrasts with N- and O-reactivities of amides are made for intramolecular iodoamidations of alkenes. The nucleophilicity of nitrogen of (S)-2-(iodomethyl)-1-tosylpyrrolidine was confirmed experimentally and by DFT calculation.