Synthesis of 2,5-disubstituted 3-iodofurans via palladium-catalyzed coupling and iodocyclization of terminal alkynes

摘要

2,5-Disubstituted 3-iodofurans are readily prepared under very mild reaction conditions by the palladium/copper-catalyzed cross-coupling of (Z)-β-bromoenol acetates and terminal alkynes, followed by iodocyclization. The useful intermediates conjugated enyne acetates are obtained in high yields in the transformation. Aryl-and alkyl-substituted alkynes undergo iodocyclization in good yields. The resulting iodine-containing furans can be readily elaborated to 2,3,5-trisubstituted furans.