Construction of σ-Aromatic AlB2 Ring via Borane Coupling with a Dicoordinate Cyclic (Alkyl)(Amino)Aluminyl Anion
Construction of σ-Aromatic AlB2 Ring via Borane Coupling with a Dicoordinate Cyclic (Alkyl)(Amino)Aluminyl Anion
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DOI：
10.1021/jacs.0c03179
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发表时间：
2020-05-13
影响因子：
15
通讯作者：
Kinjo, Rei
中科院分区：
文献类型：
--
作者：
Koshino, Kota;Kinjo, Rei
自2018年突破性地发现合成可装瓶的亲核铝基阴离子是可行的以来，迄今为止已经开发了一些衍生物，但仅限于二氨基和二烷基取代的物质。在此，我们报道了基于五元骨架的环（烷基）（氨基）铝基阴离子的合成。铝的二坐标中心有一对孤电子和一个未占据的3p轨道，因此它与碳烯是等电子的。我们展示了Al球上的键形成和键激活：因此，它不仅与硼烷进行电子重分配，形成一个杂原子基团13环，具有与三中心双电子AlB2键伴随的sigma-芳香性质，而且其双亲性允许在铝中心氧化添加Si-H， N-H，甚至C-C键。
Since the groundbreaking discovery in 2018 that the synthesis of a bottleable nucleophilic aluminyl anion is feasible, a handful of derivatives have been developed to date, which are, however, limited to diamino- and dialkyl-substituted species. Herein, we report the synthesis of a cyclic (alkyl)(amino)aluminyl anion based on a five-membered framework. The dicoordinate aluminum center features both a lone pair of electrons and an unoccupied 3p orbital, thus genuinely making it isoelectronic with carbenes. We show the bond formation and bond activation at the Al sphere: thus, not only does it undergo electron redistribution with borane to furnish a heteroatomic group 13 ring exhibiting a sigma-aromatic nature concomitant with a three-center two-electron AlB2 bond but also the ambiphilic nature allows for oxidative addition of Si-H, N-H, and even C-C bonds at the aluminum center.