Aluminium‐Catalyzed C(sp)−H Borylation of Alkynes

Historically used in stoichiometric hydroalumination chemistry, recent advances have transformed aluminium hydrides into versatile catalysts for the hydroboration of unsaturated multiple bonds. This catalytic ability is founded on defining reactivity with alkynes and alkenes: 1,2-hydroalumination π-system. manuscript reports hydride catalyzed dehydroborylation terminal alkynes. A tethered intramolecular amine ligand controls at centre, switching off instead enabling selective reactions alkyne C−H σ-bond. Chemoselective borylation was observed across a series aryl- alkyl-substituted (21 examples). On basis kinetic density functional theory studies, mechanism which proceeds by σ-bond metathesis between pinacolborane (HBpin) alkynyl intermediates proposed.