Copper/Palladium‐Catalyzed Cyclization/Cross‐Coupling Cascade Reaction of 2‐gem‐Dibromovinyl Aryl Selenides: Synthesis of 2‐Substituted Benzo[b]selenophenes

Abstract

AbstractCopper/palladium‐catalyzed multicomponent cyclization reactions, which combine 2‐gem‐dibromovinyl aryl selenides with a nucleophilic source, were applied to the synthesis of 2‐substituted benzo[b]selenophenes. A systematic study of the cyclization system revealed that the mutual action between copper and palladium salts is essential for the formation of products in good yields, avoiding the formation of hydrogenated benzo[b]selenophenes. The versatility of 2‐bromobenzo[b]selenophenes was also studied by palladium‐catalyzed reactions with boronic acids, Grignard reagents and methyl acrylate affording the cross‐coupled products in good yields. In addition, the reaction of 2‐bromobenzo[b]selenophene towards halogen‐lithium exchange reactions followed by the addition of aldehyde afforded the corresponding secondary alcohol.magnified image