Pd-catalyzed vinylation of aryl halides with tris(alkoxy)vinylsilanes occurs in aqueous NaOH solution through Heck coupling of the aryl, halide with the silyl olefin followed by desilylation at the Pd center or, at high temperatures, hydrolysis of the C-Si bond. Pd-mediated desilylation does not occur via B-Si elimination under these conditions.