Cobalt-Catalyzed Benzylzincation of Alkynes

Significance

Synthesis of polysubstituted al­kenes with defined stereochemistry can be a challenge using standard olefination reactions. Transition-metal-catalyzed carbometalation of alkynes has become an alternative strategy to access these important building blocks (see Review ­below). The authors add to this field by coupling benzylzinc nucleophiles and alkynes under cobalt catalysis. This reaction proceeds in moderate to good yields with high stereoselectivity during the syn-addition. The regioselectivity of the transformation is highly dependent on the structure of the alkyne.