Dehydrogenative borylation: the dark horse in metal-catalyzed hydroborations and diborations?

Metal-catalyzed hydroborations and diborations frequently give unwanted side products arising from a competing dehydrogenative borylation reaction. While catalyst development initially focused on avoiding this deleterious pathway, fine tuning of a catalyst system could provide an efficient method to generate unsaturated alkenylboronate esters, synthetically valuable synthons for the Suzuki-Miyaura cross-coupling reaction. The aim of this review is to highlight the history and development of the dehydrogenative borylation reaction in the metal-catalyzed synthesis of alkenylboronate esters.