Development of a one-pot sequential Sonogashira coupling for the synthesis of benzofurans

An efficient one-pot protocol was developed for the construction of the benzofuran system from aryl halides and protected iodophenols using carbinol-based acetylene sources. The sequence includes alternating palladium-catalyzed Sonogashira couplings and deprotection steps concluded by a ring closure. The developed one-pot procedure was compared with the stepwise approach and its efficiency was also demonstrated by the total synthesis of vignafuran, a benzofuran natural product.