Synthesis of Activated Alkenylboronates from Acetylenic Esters by CuH‐Catalyzed 1,2‐Addition/Transmetalation

Abstract

Stuck on an sp2 carbon: A new route to geometrically defined α-alkoxycarbonyl-substituted vinylboronates consists of the chemo- and stereoselective 1,2-addition of copper hydride to acetylenic esters followed by stereoretentive transmetalation with pinacolborane. This strategy is applied to the generation of an aryl acrylate intermediate in the synthesis of the antiinflammatory drug naproxen (see scheme).