A Broadened Scope for the Use of Hydrazones as Neutral Nucleophiles Using H-Bonding Organocatalysts

Using thioureas as H-bonding organocatalysts, nitroalkenes can be activated for the conjugate addition of hydrazones as neutral nucleophiles. Formaldehyde derivatives react at the azomethine carbon as expected, whereas hydrazones from enolizable aldehydes behave as ene-hydrazines and react at the alpha-carbon instead. Ionic liquids were found to decrease the reaction times considerably compared to commonly used solvents, whereas alter- native activation by Lewis acids resulted in decomposition of reactants.