KOH-Promoted Synthesis of Oxirane Functional Derivatives from Diethyl Bromomalonate and Aldehydes under Phase-Transfer Catalysis Conditions

The Darzens condensation of diethyl bromomalonate with aromatic or isoprenoid aldehydes under heterogeneous conditions (KOH/MeCN) in the presence of Bu₄NPF₆ as a recoverable phase-transfer catalyst afforded the corresponding diethyl 3-R-oxirane-2,2-dicarboxylates in high yields.