Synthesis of Furans via Indium-Catalyzed Rearrangement of Acetylenic Epoxides

Significance

Reported is a synthesis of substituted furans 4 via rearrangement of acetylenic ­epoxides 3, in which a catalytic amount of InCl₃ efficiently activates the process to afford 2,3,5-trisubstituted furans 4 in high yields. InCl₃ was shown to be super efficient among In, Cu, Au, Pt and Pd catalysts during catalyst investigations. The epoxides 3 are easily and efficiently prepared by reaction of lithium acetylides 2 with α-bromo ketones 1. The scope of this reaction was not well investigated.