A Diels–Alder reaction conducted within the parameters of aqueous organocatalysis: still just smoke and mirrors

Conducting reactions using water as solvent is a highly prized goal for the organic chemist. Based upon recent literature and our continuing interest in the field of aqueous organocatalysis, we tested the scope of an enamine based Diels–Alder reaction using (±)-nornicotine, proline, and a proline derivative as aqueous organocatalysts. Unfortunately, none of the examined catalysts under aqueous conditions proved useful, leaving the aqueous Diels–Alder reaction as an elusive goal.