| 2,1-Benzisoxazoles which are also been referred to as ‘anthranils',are one class of important heterocyclic compounds with 10-?-electron system.It has been studied that anthranil derivatives are employed in the treatment of some disorders of the central nervous system and can also be used as starting materials to prepare other heterocyclic building blocks,such as quinolinones and acridones.The researches on the synthesis of 2,1-benzisoxazoles were mainly made during 1950 s to 1990 s,and harsh reaction conditions were required in most of cases.The chemistry of 2,1-benzisoxazoles has attracted increasing attention from the synthetic community due to its high reactivity on annulation reaction and direct C-H functionalization since 2016.This thesis mainly focus on the studies toward 2,1-benzisoxazole derivatives and the following two parts are as follows:Part 1: The synthetic methods of anthranils are briefly introduced in this chapter.Besides,the cyclization of o-benzyl nitrobenzenes to 2,1-benzoisoxazoles catalyzed by iridium polypyridine complex has been preliminarily investigated on the basis of photochemistry,the yield of which could be up to 89% based on the recovered starting materials.The current reaction could proceed at room temperature and provide a mild and effective way for the synthesis of anthranils in the absence of acids or bases as additive.Part 2: The brief introduction to the annulation reactions of anthranils is described in this chapter.In addition,intramolecular cyclization of anthranils with the acetylene moiety is initially designed based on gold catalysis.However,unexpectedly,we obtain a novel macrocyclic product with C2 axis symmetry that has never been reported before.Though it is still in low yield after a series of optimization of conditions,not only does it expand the method of anthranils participating in the cyclization reactions,but laies a foundation for the cyclization of anthranils to macrocyclic products. |
PDF Full Text Request