It is well known that the enantioselective addition of diethylzinc to aldehydes with biaryldiol ligands is a standard reaction to evaluate the reactivity and enantioselectivity of newly developed chiral ligands . We chose addition of diethylzinc to benzaldehyde (22a) as the model reaction to test ligands including our newly developed (S)-L1 ~ (S)-L11 and previous (S)-BINOL using titanium tetraisopropoxide as the Lewis acid, dry dichloromethane (DCM) as the solvent at -3 o C or room temperature. As shown in Table , every ligand showed high reactivity, but the enantioselectivity was different (entries 1-12), and (S)-L2 (entry 2), (S)-L5 (entry 5) and (S)-L8 (entry 8) provided higher ee values (>90% ee). Effect of solvents was investigated (13-17), and toluene was the best solvent for the reaction (entry 13). Subsequently, the substrate scope on the enantioselective addition of diethylzinc to aldehydes (22) was investigated. As shown in Fig. , most of the tested aldehydes afforded excellent yields and good to excellent ee values. An aliphatic aldehyde, 3-phenylpropanal was used as the substrate, and it gave 84% yield and 87% ee (see (S)-23n). We found that several aldehydes provided poor ee values with (S)-L2 as the ligand, for example, 50% ee was afforded for 4-methoxybenzaldehyde. When (R)-L4 replaced (S)-L2 as the ligand, higher enantioselectivity (-91% ee) was observed (see (S)-23o). Similarly, ligands (R)-L1, (R)-L6 and (S)-L3 instead of (S)-L2 were used in the addition reactions of diethylzinc to 2-chlorobenzaldehyde, thiophene-2-carbaldehyde and cinnamaldehyde, respectively, and the corresponding ee values were obviously improved (see (S)-23p, 23q and 23r). The results show that our diverse adjustable chiral biphenyldiol ligands are very useful for enantioselective regulation of different substrates. The reaction above can tolerate various functional groups including ether, cyano, CF3, C-F, C-Cl, C-Br bonds and S-heterocycle.