Synthesis and applications in Henry reactions of novel chiral thiazoline tridentate ligands

Several novel chiral tridentate ligands containing thiazoline were efficiently synthesized from commercially available l=cysteine in high yield. These ligands were subsequently applied to the asymmetric Henry reaction of nitromethane and various aldehydes. It was found that the structures of the thiazoline ligands had a significant influence on the enantioselectivity. It was shown that the optimal catalyst for this reaction was a ligand complexed with CuCl, which was formed from chiral thiazoline with chiral aminoalcohol. At -20°C, with 10 mol% of this ligand, a product with (S)-configuration was isolated in 93% yield and 98% enantiomeric excess.