The first catalytic asymmetric addition of diethylzinc to aldehyde promoted by chiral thiourea

A series of C2-symmetric and asymmetric chiral thiourea derivatives were synthesized from commercial l-phenylalanine. All of the new compounds have been fully characterized by IR, 1H NMR, 13C NMR, MS spectra and elemental analyses. The chiral thioureas were used as chiral ligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc, the corresponding sec-alcohols were gained with excellent enantioselectivities (up to 87.1% ee) and high yields (up to 76.7%) after the conditions were optimized.