Alkali-Metal-Mediated Magnesiations of an N-Heterocyclic Carbene: Normal, Abnormal, and "Paranormal" Reactivity in a Single Tritopic Molecule
Alkali-Metal-Mediated Magnesiations of an N-Heterocyclic Carbene: Normal, Abnormal, and "Paranormal" Reactivity in a Single Tritopic Molecule
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N-杂环卡宾的碱金属介导的磁化：单个三位分子中的正常、异常和“超自然”反应性
DOI：
10.1002/ange.201507586
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发表时间：
2015
影响因子：
--
通讯作者：
Martínez-Martínez A
中科院分区：
文献类型：
--
作者：
Martínez-Martínez A
在本文中，烷基镁胺钠[Na 4 Mg 2（TMP）6（nBu）2]（TMP= 2，2，6，6-四甲基哌啶）是一种模板碱，其去质子化作用主要由其12个原子的环结构决定，使用常见的N-杂环卡宾（NHC）IPr [1，3-双（2，6-二异丙基苯基）咪唑-2-亚基]进行了研究。 值得注意的是，IPr的镁化发生在芳基取代基的对位，钠化发生在异常的C4位置，而配价键发生在正常的C2和钠之间，所有这些都在一个20原子的环结构中，容纳两个IPr 2 −。 对不同K/Mg和Na/Mg双价碱的研究发现了另外两种镁化的NHC结构，其中含有两个或三个IPr−单阴离子，通过异常的C4位点与Mg结合。协同作用在于镁化只能通过碱金属介导起作用，这些反应将镁添加到能够直接金属化NHC的小金属卡特尔中。
Herein the sodium alkylmagnesium amide [Na4Mg2(TMP)6(nBu)2] (TMP=2,2,6,6‐tetramethylpiperidide), a template base as its deprotonating action is dictated primarily by its 12 atom ring structure, is studied with the common N‐heterocyclic carbene (NHC) IPr [1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]. Remarkably, magnesiation of IPr occurs at thepara‐position of an aryl substituent, sodiation occurs at the abnormal C4 position, and a dative bond occurs between normal C2 and sodium, all within a 20 atom ring structure accommodating two IPr2−. Studies with different K/Mg and Na/Mg bimetallic bases led to two other magnesiated NHC structures containing two or three IPr−monoanions bound to Mg through abnormal C4 sites. Synergistic in that magnesiation can only work through alkali‐metal mediation, these reactions add magnesium to the small cartel of metals capable of directly metalating a NHC.