Enantioselective diethylzinc addition to aldehydes catalysed by C2- symmetric 1,2- diols

At this graduate thesis, C2-symmetric diol bidantate ligands have been synthesized in a straightforward manner through a three-step reaction with good yields. The synthesized C2-symmetric (1R,2R)-1,2-bis(2′-bromophenyl)-ethane-1,2-diol (4) ve (1R,2R)-1,2-bis(2′-phenylphenyl)ethane-1,2-diol (5) were characterized by using 1H-NMR, 13C-NMR, IR and mass spectral data. The synthesized chiral (4) and (5) ligands were evaluated in the enantioselective addition of diethylzinc to aromatic aldehydes. The enantioselective diethylzinc addition gave excellent enantioselectivity especially with 1-naphtaldehyde (%94 ee) in the catalysis of (4) and in the catalysis of (5) resulted excellent enantioselective induction with 1-naphtaldehyde and 3-chlorobenzaldehyde (%97- %98 ee). In addition to this, the catalytic activity of the ligands were evaluated in the enantioselective diethylzinc to aldehydes in the presence of Ti(IV) (>%99 ee).