Filbeck Erik, Cremer Sebastian, Jansen Moritz C F, Kaifer Elisabeth, Himmel Hans-Jörg
Inorganic Chemistry, Ruprecht-Karls University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Chemistry. 2023 Dec 22;29(72):e202302911. doi: 10.1002/chem.202302911. Epub 2023 Nov 7.
The ditriflato-diborane B (μ-hpp) (OTf) (hpp=1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate) acts as a stable surrogate of the elusive dication [B (hpp) ] , being both electrophilic (vacant boron p orbitals) and nucleophilic (filled B-B bond orbital). This combination of seemingly contrasting behaviors could be used to develop a metallomimetic diborane chemistry, with Lewis σ-basic and π-acidic substrates being bound and reduced at the diborane. Here, we report on a novel reaction type within this general theme, in which double electron transfer from the diboron unit to the boron-bound organic substrate is coupled with halide transfer in the other direction. Novel diborylated dienamines are synthesized in this way. The scope of this unprecedented reaction motif and the reaction pathways are elucidated.
双三氟甲磺酸根二硼烷B(μ-hpp)(OTf)(hpp = 1,3,4,6,7,8-六氢-2H-嘧啶并[1,2-a]嘧啶阴离子)作为难以捉摸的二价阳离子[B(hpp)]₂的稳定替代物，兼具亲电性(空的硼p轨道)和亲核性(充满电子的B-B键轨道)。这种看似相反行为的组合可用于发展一种模拟金属的二硼烷化学，使Lewis σ-碱和π-酸底物在二硼烷处结合并被还原。在此，我们报道了在这一总体主题下的一种新型反应类型，其中从二硼单元到与硼相连的有机底物的双电子转移与另一个方向的卤化物转移相耦合。通过这种方式合成了新型的双硼化二烯胺。阐明了这种前所未有的反应模式的范围和反应途径。
