The merger of electro-reduction and hydrogen bonding activation for a radical Smiles rearrangement

The reductive activation of chemical bonds at less negative potentials provides a foundation for high functional group tolerance and selectivity, and it is one of the central topics in organic electrosynthesis. Along this line, we report the design of a dual-activation mode by merging electro-reduction with hydrogen bonding activation. As a proof of principle, the reduction potential of N-phenylpropiolamide was shifted positively by 218 mV. Enabled by this strategy, the radical Smiles rearrangement of N-arylpropiolamides without external radical precursors and prefunctionalization steps was accomplished. [DBU][HOAc], a readily accessible ionic liquid, was exploited for the first time both as a hydrogen bonding donor and as a supporting electrolyte.