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P-Phos [2,2′6,6′-四甲氧基吡啶-4,4′-二(二苯基膦)-3,3′-联吡啶]是一类对空气稳定的杂环磷配体。本文以较简单的方法合成了rac-P-Phos配体,并用IR、1H NMR、13C NMR和元素分析等方法进行了表征。首次将P-Phos配体用于催化卤代芳烃和胺的偶联反应中。通过对碱、溶剂和催化剂用量等的筛选,确立了最优化的反应条件。配体对溴代芳烃的催化效果很好,对具有吸电子存在的氯代芳烃,特别是氯代吡啶同样得到了令人满意的结果,分离产率高达97%。催化剂对水和空气的稳定性很好,对胺偶联反应的催化效果很理想,因此是一种有应用前景的催化剂。 相似文献
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在B3LYP/6-31G^*水平上以二甲醚(Me2O)模型四氢呋喃(THF)对烯烃在THF溶液中硼氢化反应的机理进行了研究。计算结果发现,烯烃通过类似SN2的交换过程中从醚与BH3的构成的配合物获得BH3结合成π配合物中间体,这交换是整个硼氢化反应的决速步骤。 相似文献
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2H-1,2,3-Diazaphospholes 3a-3h were prepared from various ketone acylhydrazones and phosphorus trichloride in the presence of triethylamine. Compounds 3 underwent feasible hetero-Diels-Alder reactions with cyclopentadiene to afford the respective anellated [1,2,3]diazaphospholes 4a--4d as well as 4a‘--4d‘ in moderate yields. The endo rule in the reaction was observed under kinetic control conditions. 相似文献
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The reactive intermediate cyclopropylidene, generated quickly by the reactions of dihalocyclopropanes with lithium or magnesium under ultrasonic irradiation, can be trapped by olefins and the corresponding spriopentane derivatives are obtained, Based on the identification of the intermediate and the products of the reaction, a mechanism is proposed that the radical intermediate should be generated at first via a single electron transfer process, sequentially it gains another electron from the metals to form the carbenoid intermediate which then leads to the main products by insertion, addition or rearrangement. On the other hand, it can also abstract the hydrogen atom from the solvent to form the corresponding monohalide which then converts into the cyclopropane derivatives. Discussions on and verifications for the reaction mechanism are given in this paper. 相似文献
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