A Versatile Route to 3,3‐Disubstituded Phthalides Via Arylogous Michael Addition Catalyzed by Organic Base

The 3,3‐disubstituted phthalide scaffold, a privileged structure in medicinal chemistry and natural product synthesis, serves as a key motif in many bioactive compounds. Leveraging the solvent‐dependent pKa modulation of organic bases, this study introduces a mild, organocatalytic Michael addition protocol for coupling diverse 3‐arylphthalides with Michael acceptors. The method demonstrates broad functional group tolerance, accommodating electron‐donating and electron‐withdrawing substituents. The versatility of this methodology is highlighted by mild reaction conditions, short reaction times, and gram‐scale feasibility. Finally, the approach may open the gate to asymmetric catalysis, offering access to enantiomerically enriched phthalides.