Copper-catalyzed addition of diboron reagents to alpha,beta-acetylenic esters: efficient synthesis of beta-boryl-alpha,beta-ethylenic esters

The efficient copper-catalyzed addition reaction of bis(pinacolato) diboron to alpha,beta-acetylenic esters has been developed, which produces the corresponding beta-borylated-alpha,beta-ethylenic esters in high yields under mild reaction conditions.