Exploring Superacid-Promoted Skeletal Reorganization of Aliphatic Nitrogen-Containing Compounds

Here we report a method to reorganize the core structure of aliphatic unsaturated nitrogen-containing substrates exploiting polyprotonation in superacid solutions. The superelectrophilic activation of N-isopropyl systems allows for the selective formal C_sp3−H activation/cyclization or homologation / functionalization of nitrogen-containing substrates. This study also reveals that this skeletal reorganization can be controlled through protonation interplay. The mechanism of this process involves an original sequence of C−N bond cleavage, isopropyl cation generation and subsequent C−N bond and C−C bond formation. This was demonstrated through in situ NMR analysis and labelling experiments, also confirmed by DFT calculations.