Copper-Catalyzed Formal Allylboration Of Arylethynes

Copper-catalyzed formal carboboration of alkynes with bis(pinacolato)-diboron and electrophiles has been one of most important methods to construct multisubstituted alkenylboron compounds.In this research area,various electrophiles including alkyl halides,aryl halides,and benzyl halides have been reported.In this thesis,we have succeeded in copper-catalyzed formal allylboration of terminal alkynes using cheap and easily available reagents,allyl bromides or sulfonates,as electrophiles.This method exhibits good regio-/stereoselectivity and good functional group tolerance for various substituents on the aromatic rings of arylethynes.Through this strategy,various arylsubstituted trisubstituted vinyl pinacol boronic esters with 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 applied to further transformations such as Suzuki coupling,oxidation,halogenation,and so on,leading to various important compounds.