Base-Controlled Selective Conversion of Michael Adducts of Malonates with Enones in the Presence of Iodine

An efficient base-controlled selective conversion of the Michael adducts of malonates with enones in the presence of iodine is reported. Highly functionalized cyclopropane, oxetane, and α-hydroxylmalonate derivatives are obtained selectively using DBU, Na₂CO₃, and NaOAc as the base, respectively. O₂ was identified to be crucial to the formation of oxetane and α-hydroxylmalonate derivatives.