The Study Of Reactivities Of Methylenecyclopropanes, Synthesis Of Novel Chiral Oxazoline Ligands And Their Applications

This dissertation is mainly divided into two sections. The first section is the reactions of methylenecyclopropanes (MCPs), it consists of four chapters.In Chapter 1, the PdC12-promoted reactions of MCPs bearing diaryl substituents on the terminal double bond were carefully investigated and the employed solvents can significantly affect the reaction outcomes. It was found that a series of dimericπ-allylpalladium(II) complexes can be obtained in good to high total yields, most of them have been characterized by X-ray crystal structure diffraction. One of these Pd complexes has also been applied in the Suzuki-Miyaura coupling reaction at room temperature and proved to be quite effective.In Chapter 2, the aminochlorination of MCPs in CO2 atmosphere using N, N-dichlorotoluenesulfonamine (TsNCl2) as the aminochlorination reagent at room temperature was investigated. The present process completely took the advantage of the green benign reaction conditions in the absence of any catalyst and solvent. The normal ring-remaining aminochlorinated products along with/without the ring-opened aminochlorinated products can be obtained in moderate to good total yields.In Chapter 3, it was found that methylenecyclopropylcarbinols with treatment of multifluorosulfonyl fluoride and Et3N can obtain the methylenecyclobutyl fluorides and methylenecyclobutyl methylenecyclopropylmethyl ethers in good to high total yields. The plausible mechanism was proposed based on the obtained results.In Chapter 4, the multi-components reaction of methylenecyclopropylcarbinols with N-tosyl imines was carried out. It was found that the corresponding products bearing 3-oxa-bicyclo[3.1.0]hexane units generated from this reaction. Based on the obtained results, a plausible mechanism for this transformation of methylenecyclopropylcarbinols is proposed.As the second section of the dissertation, we engaged in the studies of the design of novel ligands and their application in asymmetric catalysis. A series of novel chiral oxazoline-Schiff base ligands has been designed and successfully synthesized, and their application for the asymmetric chlorination ofβ-ketoesters showed excellent catalytic activities with good enantioselectivities.