The cobalt-catalyzed allylzincation reaction of 1-phenyl-1-alkynes proceeds with high regio- and stereoselectivity. The resultant alkenylzinc species undergo further functionalization upon treatment with electrophiles.
Cobalt salts such as cobalt(II) chloride catalyze allylzincation reactions of 1-aryl-1-alkynes. The allylzincations proceed in a syn fashion to form 2-allyl-1-aryl-1-alkenylzinc species. Other internal alkynes such as 6-dodecyne or 2-nonyn-1-ol are much less reactive than 1-aryl-1-alkynes.