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

Abstract

The 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 ν CO band patterns, DFT calculations indicated that these isomers correspond to rotamers around the MnÀ NHC bond and their different spectroscopic properties were rationalized by the occurrence of attractive π(C=C)•••π*(C�O) or σ(CÀ H)•••π*(C�O) intramolecular interligand interactions. The evaluation of this complex in catalytic hydrosilylation of acetophenone using Ph 2 SiH 2 under UV irradiation led to the formation of the corresponding (R)-alcohol with low enantioselectivity.