Stereoselective Access to Tetrasubstituted Alkenylboronates via Cobalt-Catalyzed, Regiodivergent Syn -Borylfunctionalization of Internal Alkynes

We report the first cobalt-catalyzed, ligand-controlled, regiodivergent syn-borylfunctionalization of readily available internal alkynes with bis(pinacolato)diboron and electrophiles. This method offers a direct and stereoselective route to highly functionalized tetrasubstituted alkenylboronates. Furthermore, employing chiral diamine ligands enables precise control over either the initial atroposelective syn-borylalkylation or the subsequent enantioconvergent alkylation step. This strategy offers efficient access to two distinct chiral architectures: atropisomeric alkenylboronates and tetrasubstituted alkenylboronates bearing allylic stereocenters. The resulting alkenylboronates serve as versatile precursors for further diversification through various cross-coupling reactions, enabling the rapid assembly of valuable tetrasubstituted alkenes.