Studies On The Synthesis Of Halogenated Trifluoromethylated Pyrroles And Novel Chiral Pincer Ligands

The halogenated pyrrole ring is a pivotal structural unit of many pharmacologically active natural products,bioactive molecules,and organic building blocks in organic synthesis.On the other hand,the development of a methodology for the synthesis of heterocyclic compounds bearing a trifluoromethyl or perfluoroalkyl group has received much attention recently since the introduction of these groups in organic molecules often improves their biological activities for medicines and agrochemicals.Therefore,the development of an effective method to directly construct a pyrrole ring with a trifluoromethyl group and a halogen atom has a certain significance,and provides more possibilities for the drug screening of bioactive molecules.In the first part of this dissertation,an easy two-step,one-pot synthesis of halogenated trifluoromethylated pyrroles is realized by sequential intermolecular hydroamination reaction of 2-trifluoromethyl-1,3-enynes with aliphatic primary amines under mild reaction conditions,and NXS mediated oxidative cyclization of the hydroamination product.And by further derivatization and conversion,the different triaryl-substituted trifluoromethyl pyrrole compounds with certain aggregation-induced fluorescence effects can be synthesized through two sequential Suzuki coupling reactions of halogenated trifluoromethylated products with aryl boric acid,which has potential applications in the field of photoelectric materials.In recent years,pincer ligands have attracted much attention because pincer-type ligands can form stable complexes through their chelation with metals.These complexes also exhibit high catalytic activity in many reactions.Combined with the experience of the synthesis of chiral phosphine ligands of our group,we designed the synthesis of chiral pincer nitrogen ligands using chiral t-butyl sulfinamide as a chiral auxiliary.In the second part of the dissertation,we initially attempted the design and the synthesis of chiral bis-alkyl amine pincer ligands and its metal complexes.A new method for the synthesis of bis-alkyl amine chiral pincer ligands has been developed.It has been found that chiral bis-alkyl amine pincer ligand can undergo transmetalation with organic gold?I?compounds after lithiation to form chiral organic gold?I?complex.Based on this work,we also completed the synthesis of N-aryl tert-butyl sulfenamide ligands and chiral bipyridine N₄ ligands.