Silver catalyzed proto- and sila-Nakamura-type α-vinylation of silyl enol ethers with dichloroacetylene. Divergent formation of stereochemically pure tri- and tetrasubstituted olefins

•Silver catalyzed activation of dichloroacetylene towards addition.•Highly trans selective addition of enol ether across dichloroacetylene.•Silyl versus proton transfer controlled via solvent.•Highly functionalized tri- and tetrasubstituted alkenes selectively obtained.•Unusual CH silylation observed in select cases.