N‐Heterocyclic Carbene‐Assisted Reversible Migratory Coupling of Aminoborane at Magnesium
N‐Heterocyclic Carbene‐Assisted Reversible Migratory Coupling of Aminoborane at Magnesium
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N—杂环卡宾—镁下氨基硼烷的辅助可逆迁移偶联
DOI：
10.1002/anie.202211496
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Gilliard, Jr, Robert J.
中科院分区：
文献类型：
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作者：
Obi, Akachukwu D.;Frey, Nathan C.;Dickie, Diane A.;Webster, Charles Edwin;Gilliard, Jr, Robert J.
对氨基硼烷镁的N-杂环卡宾（NHC）加合物进行了合成和理论研究，其中涉及到一个罕见的在正常价区元素中可逆迁移插入的例子.（NHC）Mg（N（SiMe 3）2）2（1）和二甲胺硼烷反应生成三酰胺加合物（NHC-BN）Mg（NMe 2BH 3）（N（SiMe 3）2）（2; NHC-BN = NHC-BH 2NMe 2）。除了Me 2N = BH 2捕获在theNHCC−Mg键，机制研究表明氨基硼烷迁移插入从RMg（NMe 2BH 2NMe 2BH 3）中间体的可能性。为了阐明这些过程，合成了卡宾配合物（NHC）Mg（NMe 2BH 3）2（8）和（NHC）Mg（NMe 2BH 2NMe 2BH 3）2（9），并在9中观察到Me 2N = BH 2在Mg-N和NHCC-Mg键之间的动态迁移。这种不寻常的可逆迁移插入可能是由−{NMe 2BH 2NMe 2BH 3}阴离子中的不同电荷定位以及NHC在刘易斯酸性镁物质存在下可逆捕获Me 2N = BH 2的能力引起的。
A combined synthetic and theoretical investigation of N‐heterocyclic carbene (NHC) adducts of magnesium amidoboranes is presented, which involves a rare example of reversible migratory insertion within a normal valents‐block element. The reaction of (NHC)Mg(N(SiMe3)2)2(1) and dimethylamine borane yields the tris(amide) adduct (NHC−BN)Mg(NMe2BH3)(N(SiMe3)2) (2; NHC−BN = NHC−BH2NMe2). In addition to Me2N=BH2capture at theNHCC−Mg bond, mechanistic investigations suggest the likelihood of aminoborane migratory insertion from an RMg(NMe2BH2NMe2BH3) intermediate. To elucidate these processes, the carbene complexes (NHC)Mg(NMe2BH3)2(8) and (NHC)Mg(NMe2BH2NMe2BH3)2(9) were synthesized, and a dynamic migration of Me2N=BH2between Mg−N andNHCC−Mg bonds was observed in9. This unusual reversible migratory insertion is presumably induced by dissimilar charge localization in the−{NMe2BH2NMe2BH3} anion, as well as the capacity of NHCs to reversibly capture Me2N=BH2in the presence of Lewis acidic magnesium species.