Efficient synthesis of alkylboronic esters via magnetically recoverable copper nanoparticles-catalyzed borylation of alkyl chlorides and bromides

We report a magnetically separable Cu nanocatalyst (Fe-DOPA-Cu) for the borylation of alkyl halides with alkoxy diboron reagents, providing alkylboronic esters in high yields, with broad functional-group tolerance under mild reaction conditions. The procedure is also applicable to the borylation of benzyl chlorides and bromides. Radical-clock experiments support a radical-mediated process. Easy recycling of the catalyst resulted in no significant loss of activity up to ten runs.