Study On The Synthesis Of Isoxazoline Derivatives By Halooxygenation Of Unsaturated Ketoximes

Isoxazolines have a wide range of applications and extremely important roles in agriculture,medicine,catalyst ligands and electrochemistry.Therefore,how to efficiently synthesize isoxazoline compounds is one of the important topics in organic synthesis.The halooxygenation reaction of unsaturated ketoximes is a highly efficient and convenient method for synthesizing isoxazoline compounds with high atomic economy.Based on the literature review,this paper further proposes a strategy for the synthesis of halogenated isoxazolines using halooxygenation of unsaturated ketoximes by focusing on the 1,2-bifunctionalization of olefins.This thesis mainly includes the following contents:In the first part,the application and research progress of isoxazolines in organic synthesis in recent years were introduced.In the second part,an efficient intramolecular iodooxygenation of unsaturated ketoximes has been achieved through the activation of iodine by tert-butyl hydroperoxide,yielded various types of synthetically versatile iodinated isoxazolines.The reaction took unsaturated ketoximes and iodine as starting materials,tert-butyl hydroperoxide as oxidant,and water as solvent to react at room temperature for 15 h to obtain corresponding iodinated isoxazolines in a yield of 22% to 95%.The reaction used cheap and easily available elemental iodine as the iodine source,environmentally friendly tert-butyl hydroperoxide as the oxidant,green non-polluting water as the solvent,the process did not require catalyst participation,the reaction conditions were mild,the atomic economy was high and the resulting the organic synthesis of less than the synthesis of iodinated isoxazolines provided a green synthetic method.In the third part,a new free radical reaction for the synthesis of brominated isoxazoline was developed.Using unsaturated ketoximes and ethyl 2-bromoisobutyrate as starting materials,1,10-phenanthroline as ligand,sodium carbonate as base and acetonitrile as solvent,under the catalytic action of copper(II)trifluoromethanesulfonate,the reaction was carried out at 80 °C for 15 h and the corresponding brominated isoxazoline compounds were obtained in a yield of 52% to 92%.The reaction used ethyl 2-bromoisobutyrate as a bromine radical precursor to provide a simple method for the synthesis of bromoisoxazolines.