Zinc-Catalyzed Multicomponent Reactions: Easy Access to Furyl-Substituted Cyclopropane and 1,2-Dioxolane Derivatives

A convenient synthesis of cyclopropyl-substituted furan derivatives by a zinc-catalyzed three-component coupling of 1,3-dicarbonylic compounds, 2-alkynals and alkenes is reported. A sequence consisting of an initial Knoevenagel condensation, cyclization, and a final cyclopropanation reaction would account for the formation of the final products. In most cases, this multicomponent process proceeds in good yield under mild reaction conditions and in the presence of a low catalyst loading. The efficient formation of 1,2-dioxolane derivatives by the zinc-promoted aerobic oxidation of some cyclopropane derivatives is also reported. The 1,2-dioxolane derivatives are also available by a four-component reaction.