Iron(II)‐Catalyzed Asymmetric Hydrosilylation of Acetophenone
Four new ligands containing a pentasubstituted cyclopentadiene tethered to a stereogenic diamine unit have been prepared and used in the iron-catalyzed enantioselective hydrosilylation of acetophenone. Catalytically active species have been generated in situ starting from various sources of iron. Fe(acac)2 was the catalyst precursor of choice, whereas other simple FeII or FeIII compounds resulted in significantly lower or no catalytic activity. Quantitative conversions were obtained working with 4 mol-% Fe at room temp. and phenylsilane as the reducing agent. Under these conditions, ligand 4 afforded an enantioselectivity of 37 % ee. Attempts to isolate the single-component Fe complexes containing ligands 3–6 have failed so far.