Enantioselective addition of diethylzinc to aldehydes catalyzed by d-glucosamine derivatives: Highly pronounced effect of trifluoromethylsulfonamide

We present the synthesis of β-hydroxy sulfonamides derived from d-glucosamine and their application as ligands in titanium tetraisopropoxide promoted enantioselective addition of diethylzinc to benzaldehyde and selected aromatic and aliphatic aldehydes. The reaction is highly enantioselective for some aromatic aldehydes and enantiomeric excess up to 99% was obtained. We present the synthesis of β-hydroxy sulfonamides derived from d-glucosamine and their application as ligands in titanium tetraisopropoxide promoted enantioselective addition of diethylzinc to benzaldehyde and selected aromatic and aliphatic aldehydes. The N-trifluoromethylosulfonamido- d-glucosamine derivative is one of the most active ligands known and only 1 mol% of the ligand is sufficient for efficient catalysis of diethylzinc addition. The reaction is highly enantioselective for some aromatic aldehydes and enantiomeric excess up to 99% was obtained.