Design And Synthesis Of New Chiral Phosphorus Ligand Applied To Asymmetric Hydrogenation Synthetical Of Chiral Pesticides

Single enantiomers of chiral pesticides have advantages such as high effectiveness, more safe to crops and environment, also have the advantage of atom economy, which is consistent with the current trend of pesticides. Chiral ligands applied to asymmetric catalysis catalyzed by transition metal is an important way to synthesize chiral pesticides. At present, chiral phosphorus ligands develop rapidly, some of them have applied to industry, However, their application in pesticides is less, which will have broad development prospects. In this paper, bidentate Phosphorus ligand and diphosphite ligand were designed with norbornene skeleton, finally diphosphite ligand was synthesized and determined its effect to seven methylesters of 2-acetamido-3-arylacrylic acid and dimethyl itaconate in asymmetric hydrogenation which is the general method to evaluate its asymmetric induction activity. This paper also preliminary discussed the effect of ligand structures on the hydrogenation and coordination relationship between ligand and transition metal. The main results were as follows:1. 2,5-norbornadiene was oxidized by jones reagent, then reduced by BH3·THF, racemate diol was prepared and reacted with chiral chlorinated phosphite binaphthol ester, eventually the lignd was synthesized. No article reported the synthesis of this lignd and its asymmetric hydrogenation.2. The ligand didn't performe catalytic activity to methylesters of 2-acetamido-3- arylacrylic acid in Rh(I) catalyzed asymmetric hydrogenation, got 91% ee to dimethyl itaconater in substrates/catalyst for 100/1.3. Product configurations after hydrogenation is relevant with the configurations of side chiral group, while irrelevant with the skeleton configurations.4. Coordination occurred between ligands and transition metal in asymmetric hydrogenation, but their relationship may not be chelating or not chelating dominant, for that chelation can significantly improve the asymmetric induction activity of the ligand. This conclusion can provide valuable guidance to the design and synthetic of efficient chiral phosphorus ligands.