Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871 (China).
Angew Chem Int Ed Engl. 2014 May 26;53(22):5634-8. doi: 10.1002/anie.201310116. Epub 2014 Apr 7.
Metallacyclopentadienes have attracted much attention as building blocks for synthetic chemistry as well as key intermediates in many metal-mediated or metal-catalyzed reactions. However, metallacyclopentadienes of the alkaline-earth metals have not been reported, to say nothing of their structures, reaction chemistry, and synthetic applications. In this work, the first series of magnesiacyclopentadienes, spiro-dilithio magnesiacyclopentadienes, and dimagnesiabutadiene were synthesized from 1,4-dilithio 1,3-butadienes. Single-crystal X-ray structural analysis of these magnesiacycles revealed unique structural characteristics and bonding modes. Their reaction chemistry and synthetic application were preliminarily studied and efficient access to amino cyclopentadienes was established through their reaction with thioformamides. Experimental and DFT calculations demonstrated that these magnesiacyclopentadienes could be regarded as bis(Grignard) reagents wherein the two Mg-C(sp(2)) bonds have a synergetic effect when reacting with substrates.
金属茂环戊二烯作为合成化学的构建块以及许多金属介导或金属催化反应中的关键中间体引起了广泛关注。然而，尚未报道碱土金属的金属茂环戊二烯，更不用说它们的结构、反应化学和合成应用了。在这项工作中，首次通过 1,4-二锂代 1,3-丁二烯合成了一系列镁茂环戊二烯、螺二锂代镁茂环戊二烯和二镁丁二烯。这些镁环的单晶 X 射线结构分析揭示了独特的结构特征和键合模式。初步研究了它们的反应化学和合成应用，并通过它们与硫代甲酰胺的反应建立了高效合成氨基环戊二烯的方法。实验和 DFT 计算表明，这些镁茂环戊二烯可以被视为双(格氏试剂)，其中两个 Mg-C(sp(2))键在与底物反应时具有协同效应。
