Palladium-Catalyzed Multicomponent Assembly of ( Z )-Alkenylborons via Carbopalladation/Boronation/Retro-Diels-Alder Cascade Reaction.

A palladium-catalyzed multicomponent cascade reaction of aryl iodides, oxanorbornadiene, and diborns to access ( Z )-alkenylborons is reported. This transformation proceeds through the sequential carbopalladation/boronation/retro-Diels-Alder domino reaction. The oxanorbornadiene used in this reaction serves as an acetylene surrogate, which is generated via a retro-Diels-Alder reaction. Such a stereoselective and scalable approach has a wide range of functional group tolerance and good substrate universality.