Copper-catalyzed reactions of β-alkoxy/phenoxy enones with dimethyl diazomalonate

Authors: FÜSUN ŞEYMA KIŞKAN

Abstract: 2,3-dihydrofurans were synthesized from carbonyl-ylides via 1,5-electrocyclization reactions with high yields. Dimethyl diazomalonate was reacted with several β-alkoxy and/or β-phenoxy α,β-unsaturated compounds in the presence of Cu(acac)$_{2}$ as a catalyst. From the reaction of β-methoxy enone with diazo compound, dioxole, and Cα-H insertion products were also obtained as side products along with 2,3-dihydrofuran derivative. When the unsaturated compound has an ester and a ketone group, only one dihydrofuran derivative was formed, which occurred by the 1,5-ring closure of keto-carbonyl ylide. Dihydrofuran derivative from the formation of ester carbonyl ylide in the reactions was not obtained.

Keywords: Carbene, metal-carbenoid, carbonyl ylide, 2,3-dihydrofuran, cycloaddition

Full Text: PDF