Copper‐Catalyzed Regioselective Formal Allylboration of Aryl‐Substituted Terminal Alkynes with Bis(pinacolato)diboron and Allyl Halides/Sulfonates

Abstract A copper‐catalyzed formal allylboration of terminal alkynes using allyl bromides or sulfonates as electrophiles has been achieved. This method exhibits good regio‐/stereoselectivity and good functional‐group tolerance for various substituents on the aromatic rings of arylethynes. Through this strategy, various trisubstituted vinyl pinacol boronic esters with a 1,4‐diene skeleton have been constructed. In order to demonstrate the utility of this method, the resulting 1,4‐dienes with boron substitution were further used in transformations such as Suzuki coupling, oxidation, halogenation, and so on, leading to various important compounds.