Homo-Diels-Alder reactions of 2,4,6-tri-tert-butyl-1,3,5-triphospha-Dewar-benzene
Homo-Diels-Alder reactions of 2,4,6-tri-tert-butyl-1,3,5-triphospha-Dewar-benzene
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DOI：
10.1016/s0022-328x(96)06565-5
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发表时间：
1997-02-15
影响因子：
2.3
通讯作者：
Kruger, C
中科院分区：
文献类型：
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作者：
Binger, P;Leininger, S;Kruger, C
当使1，3，5-三磷酰-杜瓦瓶-苯衍生物4与缺电子炔如乙炔二羧酸二甲酯或丙酸甲酯或与叔丁基磷酰乙炔反应时，均-狄尔斯-桤木反应在非常温和的条件下发生。得到的[2 + 2 + 2]-环加合物5、6和8可以以优异的产率分离并且区域选择性地形成。此外，[4 + 2 + 2]-环加成的第一个实例已经通过4与三叔丁基氮杂环丁二烯10的反应实现，其产生两个外环加成物11和12。环加合物12在硅胶柱色谱条件下不稳定，并经历重排成异构体13。
Homo-Diels-Alder reactions take place under very mild conditions when the 1,3,5-triphospha-Dewar-benzene derivative 4 is allowed to react with electron-deficient alkynes, such as dimethyl acetylenedicarboxylate or methyl propyonate, or with tert-butylphosphaacetylene. The resultant [2 + 2 + 2]-cycloadducts 5, 6, and 8 can be isolated in excellent yields and are formed regioselectively. Moreover, the first example of a [4 + 2 + 2]-cycloaddition has been realized by the reaction of 4 with tri-tert-butylazacyclobutadiene 10 which yields the two exo-cycloadducts 11 and 12. The cycloadduct 12 is unstable under the conditions of column chromatography on silica gel and undergoes rearrangement to the isomer 13.