Substrate‐Assisted,Transition‐Metal‐Free Diboration of Alkynamides with Mixed Diboron: Regio‐ and Stereoselective Access to trans‐1,2‐Vinyldiboronates

A substrate‐assisted diboration of alkynamides using the unsymmetrical pinacolato‐1,8‐diaminonaphthalenato diboron (pinBBdan) is described. The transition‐metal‐free reaction proceeds in a regio‐ and stereoselective fashion to exclusively afford trans ‐vinyldiboronates in good to excellent yields. Notably, Bdan and Bpin are installed on the α‐ and β‐carbon atoms, respectively.