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 Fe II or Fe III 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.