A Cu₂O nanoparticle catalyzed borylation of activated and unactivated alkyl bromides is developed, using bis(pinacolato)diboron as a boron source. To the best of our knowledge this is the first report of a heterogeneous Cu₂O nanocatalyst applied in the direct synthesis of primary and secondary alkylboronic esters. Our catalytic system features mild reaction conditions, high yield (nearly 100%) and the absence of ligands which otherwise are essential in homogenous catalysis.