A new chiral catalyst for the enantioselective addition of diethylzinc to aldehydes

β-amino alcohol motif is typical of numerous chiral catalysts used in asymmetric synthesis [ ], and they are the first choice when considering the addition of diethyl zinc to aldehydes, a classical reaction test for new ligands employable in asymmetric catalysis [ ]. Recently, the use of functionalized magnetic nanoparticles led to new catalysts that combine advantages of both homogeneous and heterogeneous catalysis [ ]. In the past years we were involved in the development of a novel versatile, magnetically recoverable β-amino alcohol ‘nanocatalyst’. We focused on the design and synthesis of ligands bearing, in addition to a fine-tunable catalytic site, a functionality (an alkoxysilane group) for their covalent anchoring to magnetite nanoparticles (Fig 1-A). Before the immobilization of the catalyst on the nanoparticles we dealt with the design and the optimization of the ligands, and after an extensive fine-tuning process we selected the structure 1 (Fig 1-B) as an excellent chiral ligand in the addition of diethylzinc to benzaldehyde (yields: >95%, ee: >95%). We finally confirmed the validity of the optimization process employing the selected ligand in the addition of diethylzinc to a family of aldehydes leading to outstanding results (Fig 1-C).