Efficient and Functional‐Group‐Tolerant Synthesis of Substituted Furans through the Pd‐Catalyzed 5‐exo‐dig Cyclization/Coupling of γ‐Acetylenic β‐Keto Esters with (Hetero)Aryl Bromides

Abstract

We report an efficient protocol for the synthesis of 2,3,5‐trisubstituted furans through the reaction of readily available γ‐acetylenic β‐keto esters with aryl and heteroaryl bromides. The reaction, which involves a 5‐exo‐dig cyclization, coupling, and isomerization of a double bond, proceeds smoothly with very low catalyst loading (0.1 mol‐%), and shows excellent functional‐group tolerance.