Synthesis of Isotopically Labeled (E)-β,γ-Unsaturated Esters with Total or High Diastereoselectivity by Using Samarium Diiodide

A simple, efficient, highly diastereoselective method for preparing (E)‐α,δ‐dideuterio‐β,γ‐unsaturated esters: SmI2‐promoted reduction/elimination of α‐halo‐β‐hydroxy‐γ,δ‐unsaturated esters in the presence of D2O (see scheme). This provides the desired products in which the C−C double bond is generated with total or high diastereoselectivity.