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降冰片烯-顺-5,6-二酸酐(简称NA)由环戊二烯与顺丁烯二酸酐经双烯合成制得。由O·Diels和K.Alder首先报道过的双烯合成反应(Diels-Alder反应,简称DA反应),为六元环化合物的合成提供了一条理想的途径,它方法简便,产率高,立体专一性和定位选择性强,在合成上有广泛的用途;这个反应的机理,既非离子型,又不同于自由基,而是协同机理的周环反应—4+2体系环加成反应,它已成为Woodward和Hoffmam轨道对称守恒原理的重要支柱,DA反应在理论上也很受重视,每年发表的研究论文仍然很多。所以,选择DA反应利用核磁作为教学实验,不但内容新颖且在理论联系实际上也具有典型
Norbornene - cis-5,6-dianhydride (referred to as NA) from cyclopentadiene and maleic anhydride by diene synthesis in the system. The Diels-Alder reaction (DA reaction), first reported by O Diels and K. Alder, provides an ideal route for the synthesis of six-membered ring compounds. It has the advantages of simple method, high yield, three-dimensional Specificity and orientation selectivity, has a wide range of uses in the synthesis; the mechanism of this reaction is neither ionic nor free radical, but synergistic cyclization -4 +2 system cycloaddition reaction , Which has become an important pillar of Woodward and Hoffmam principle of orbital symmetry conservation. The DA reaction is also valued in theory. There are still many published research papers each year. Therefore, the choice of DA reaction using NMR as a teaching experiment, not only novel and in theory also actually has a typical