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An enantioselective (52-98% ee) Michael addition between cyclic β-diones and α,β-unsaturated enones was established in the presence of quinine-based primary amine or squaramide. A variety of cinnamones were smoothly converted into the desired 3,4-dihydropyrans in moderate to high yields (63-99%). Chalcones were also suitable acceptors and gave rise to the expected adducts in satisfactory yields (31-99%). The resulting adducts readily underwent further modification to form fused 4H-pyran or 2,3-dihydrofuran.

Enantioselective Michael Addition of Cyclic β-Diones to α,β-Unsaturated Enones Catalyzed by Quinine-Based Organocatalysts