Half‐Sandwich Manganese Complex Bearing Fused Oxazoline‐NHC Ligand: Conformational Analysis and Evaluation in Asymmetric Ketone Hydrosilylation

Abstract

AbstractThe first manganese complex bearing a chiral N‐heterocyclic carbene (NHC) ligand was prepared and studied by spectroscopic methods and X‐ray diffraction. While IR spectroscopy revealed the existence of two isomers in solution with distinct νCO band patterns, DFT calculations indicated that these isomers correspond to rotamers around the Mn−NHC bond and their different spectroscopic properties were rationalized by the occurrence of attractive π(C=C)⋅⋅⋅π*(C≡O) or σ(C−H)⋅⋅⋅π*(C≡O) intramolecular interligand interactions. The evaluation of this complex in catalytic hydrosilylation of acetophenone using Ph2SiH2 under UV irradiation led to the formation of the corresponding (R)‐alcohol with low enantioselectivity.