Cobalt-Catalyzed Three-Component Reductive Coupling of Aldehydes, Allenes, and Aryl Halides

A Co-catalyzed reductive three-component coupling of aldehydes, allenes, and aryl halides is described. The reaction is both regio- and stereoselective and produces stereodefined trisubstituted alkenylsilanes that can be converted into trisubstituted alkenes. Broad functional group tolerance was demonstrated through 40 examples, with an oxidative addition mechanism proceeding through halide abstraction.