Synthesis And Application Of Novel NNP Oxazoline Ligands

The N atom of oxazoline possesses electron-donating property,which can coordinate with metal ions well.In addition,the chiral groups in oxazoline are close to coordination center.Based on reasons above,metal complexes with oxazoline play a large chiral inducing role in the course of catalysis.Therefore,the design and development of new classes of oxazoline type ligands are one of an important targets in asymmetric catalysis.The fluorine atom,possessing strong electronegativity and low nucleophilicity,has an important significance for changing the chemical properties and metabolic ability of medicine.Therefore,the asymmetric fluorination reaction attracts many chemists’ attention,and becomes a hot topic on chemical research.Nowadays there are many methods to achieve the asymmetric fluorination reaction,Using metal complexes with ligands has become one of the most commonly methods to achieve it.The main contents of this paper include the following three aspects:(1)We designed and synthesized a new type of NNP oxazoline ligand.The raw materials of the ligand are cheap and readily available.The synthetic conditions are mild and easily.The most importantly,the ligands are very stable to store in air for a long time..(2)By changing substituent groups of raw materials and optimizing operated reaction conditions,we developed ten NNP ligands with different substituent groups.(3)To explore the asymmetric catalysis effect of the new ligands towards the fluorination reaction of β-ketoester,we screened the metal ions,ligands,solvents in this reaction.Finally,the new type of NNP ligands can catalyze the fluorination reaction to achieve 94% of yield and 80% of ee value at most.