Syntheses of asymmetrical magnesium(i) complexes and their catalytic application in epoxide hydroboration

Abstract

A series of asymmetrical β-diketiminate ligand stabilized magnesium(I) complexes have been successfully synthesized and structurally characterized via single crystal X-ray diffraction. When they were employed as efficient catalysts in the hydroboration of aryl, alkyl and alicyl epoxides with pinacolborane (HBpin), the resultant borate ester products were obtained with high yields and high regioselectivities. The results also revealed that they showed a marked preference for the branched Markovnikov hydroborated products instead of the linear anti-Markovnikov borate esters which are typically formed in protocols involving transition metal catalysts. The preliminary hydroboration reaction mechanism has been investigated via the corresponding DFT calculation.