A Broadened Scope for the Use of Hydrazones as Neutral Nucleophiles in the Presence of 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 alternative activation by Lewis acids resulted in decomposition of ­reactants.