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.