The reaction chemistry of an unprecedented ‘inorganic cumulene’ - featuring a five-atom BNBNB chain - towards C=O (and related) multiple bonds is disclosed. In marked contrast to related all-carbon systems, the intrinsic polarity of the BNBNB chain (featuring electron-rich nitrogen and electron-deficient boron centres) enables metathesis chemistry with electrophilic heteroallenes such as CO2 and with organic carbonyl compounds. Transfer of the borylimide unit to [CO], [CS], [PP{(NDippCH2)2}] and [C(H)Ph] moieties generates (boryl)N=C=X systems (X = O, S, PP{(NDippCH2)2}, C(H)Ph), driven thermodynamically by B–O bond formation. Pairwise exchange of O and {(HCDippN)2}BN fragments occurs via consecutive [2+2] cyclo-addition/cyclo-reversion steps. An isolable complex of stoichiometry K[(boryl)NB(O)OC(H)Ph], formed via [2+2] cycloaddition to [(boryl)N=B=O]– can be shown to be an intermediate in the formation of (boryl)N=C(H)Ph, and provides corroborating evidence for a DFT-calculated mechanism proceeding via a ‘bora-Wittig’ mechanism.

中文翻译：

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B-O 键形成驱动的无机积云的复分解化学


公开了一种前所未有的“无机积云”——具有五原子 BNBNB 链——对 C=O（和相关）多个键的反应化学。与相关的全碳系统形成鲜明对比的是，BNBNB 链的本征极性（具有富电子氮和缺电子硼中心）能够与亲电异种烯（如 CO2）和有机羰基化合物进行复分解化学。硼酰亚胺单元转移到 [CO]、[CS]、[PP{（NDippCH2）2}] 和 [C（H）Ph] 部分会产生 （硼基）N=C=X 系统（X = O、S、PP{（NDippCH2）2}、C（H）Ph），由 B-O 键形成热力学驱动。O 和 {（HCDippN）2}BN 片段的成对交换通过连续的 [2+2] 环加成/环反转步骤发生。通过向 [（硼基）N=B=O] 形成的化学计量 K[（硼基）NB（O）OC（H）Ph] 的可分离复合物 – 可以证明是形成 （硼基）N=C（H）Ph 的中间体，并为通过“bora-Wittig”机制进行的 DFT 计算机制提供了确凿的证据。