Reactivity of Diphenylberyllium as a Brønsted Base and Its Synthetic Application

Diphenylberyllium [Be₃ Ph₆ ] is shown here to react cleanly as a Brønsted base with a vast variety of protic compounds. Through the addition of the simple molecules tBuOH, HNPh₂ and HPPh₂ , as well as the more complex 1,3-bis-(2,6-diisopropylphenyl)imidazolinium chloride, one or two phenyl groups in diphenylberyllium were protonated. As a result, the long-postulated structures of [Be₃ (OtBu)₆ ] and [Be(μ-NPh₂ )Ph]₂ have finally been verified and shown to be static in solution. Additionally [Be(μ-PPh₂ )(HPPh₂ )Ph]₂ was generated, which is only the second beryllium-phospanide to be prepared; the stark differences between its behaviour and that of the analogous amide were also examined. The first crystalline example of a beryllium Grignard reagent with a non-bulky aryl group has also been prepared; it is stabilised with an N-heterocyclic carbene.