Synthesis of (E)-α,β-Unsaturated Esters and Amides with Total Selectivity Using Samarium Diiodide

β-elimination of α-halo-β-hydroxyesters 1 was achieved by using samarium diiodide as a metalating reagent, and afforded di- and trisubstituted (E)-α,β-unsaturated esters 2 with total steroselectivity. This method has also been extended to the corresponding disubstituted (E)-α,β-unsaturated amides.