Magnesium amide catalyzed selective hydroboration of esters

Abstract

Magnesium amide complexes such as Mg{N(SiMe₃)₂}₂ (1) ^xylLMgN(SiMe₃)₂·THF (2) [^xylL = ArNC(NⁱPr₂)NAr; (Ar = 2,6-Me₂-C₆H₃)] and ^dippLMgN(SiMe₃)₂·THF (3) [^dippL = ArNC(NⁱPr₂)NAr; (Ar = 2,6-ⁱPr₂-C₆H₃)] are reported as highly efficient pre-catalysts for the hydroboration of a wide range of esters using pinacolborane (HBpin) under mild reaction conditions. Moreover, we have shown compound 1 catalyzed chemoselective reduction of esters in the presence of other reducible functional groups such as alkene, alkyne and nitro.