Wiebe Matthew A, Staubitz Anne, Manners Ian
Department of Chemistry, University of Victoria, 3800 Finnerty Rd, Victoria, BC, V8P 5C2, Canada.
Otto-Diels-Institute for Organic Chemistry, University of Kiel, Otto-Hahn-Platz 4, Kiel, 24118, Germany.
Chemistry. 2025 Feb 20;31(11):e202403849. doi: 10.1002/chem.202403849. Epub 2025 Jan 9.
We report on the reactivity of aminoboranes (RN=BH; R = iPr, Et, Me) with phosphine-borane adducts (PhR'PH ⋅ BH; R' = H, Ph): Sufficiently sterically unencumbered aminoboranes can accept hydrogen from phosphine-borane adducts. The hydrogen transfer results in the formation of amine-borane adducts (RNH ⋅ BH) and transient phosphinoboranes (PhR'P-BH) in situ. These phosphinoboranes undergo subsequent reactivity to yield either polyphosphinoborane, [PhPH-BH], or the linear dimer, PhPH ⋅ BH-PhP ⋅ BH. Unlike metal catalyzed phosphine-borane dehydrocoupling, which occurs at elevated temperatures (2 M, toluene, ≥100 °C, ≥24 h), these dehydrocoupling reactions occur under ambient conditions (2 M, EtO or CD, 20 °C, ≤24 h). We performed a computational mechanistic study in which we identified that this transformation potentially occurs via a P-to-N and B-to-B hydrogen transfer through a 6-membered transition state.
我们报道了氨基硼烷（RN=BH；R = 异丙基、乙基、甲基）与膦-硼烷加合物（PhR'PH ⋅ BH；R' = 氢、苯基）的反应活性：空间位阻足够小的氨基硼烷可以从膦-硼烷加合物中接受氢。氢转移导致原位形成胺-硼烷加合物（RNH ⋅ BH）和瞬态膦基硼烷（PhR'P-BH）。这些膦基硼烷随后发生反应，生成聚膦基硼烷[PhPH-BH]或线性二聚体PhPH ⋅ BH-PhP ⋅ BH。与在高温下（2 M，甲苯，≥100°C，≥24小时）发生的金属催化膦-硼烷脱氢偶联不同，这些脱氢偶联反应在环境条件下（2 M，EtO或CD，20°C，≤24小时）发生。我们进行了一项计算机理研究，其中我们确定这种转化可能通过六元过渡态经由从磷到氮和从硼到硼的氢转移而发生。
