Carbometalation: Cobalt salts catalyze benzylzincation of alkynes to afford benzylated multisubstituted alkenes with high regio‐ and stereoselectivity. The scope of the reaction is wide enough to apply unfunctionalized alkynes as well as arylacetylenes. The reaction offers a new route to the regio‐ and stereoselective synthesis of an estrogen receptor antagonist (see scheme).