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Updated: Jun 27, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
N─H or O─H Bond Activation With a Bicyclic Si4 Ring Compound
Michael Quest1, Florian Schreiner1, Alexander Hepp1
1Institut für Anorganische und Analytische Chemie, Universität Münster, Fachbereich Chemie und Pharmazie, Münster, Germany.
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The bicyclic silicon ring compound Si4{N(SiMe3)Mes}4 (Mes = 2,4,6-trimethylphenyl), a heavier analogue of cyclobutadiene, was reacted with ammonia, water, and selected alcohols. This resulted in E─H (E = N, O) bond activation, yielding saturated Si4 rings with ─NH2/─H or ─OH/─H functionalities in the case of ammonia or water, respectively. With methanol, a mixture of a saturated Si4 ring compound with ─OMe/─H functionalities and an eight-vertex methoxy-functionalized siliconoid cluster was obtained; an ethoxy-functionalized analogue was obtained from the reaction with ethanol. In contrast, the reaction between Si4{N(SiMe3)Mes}4 and phenol gave a simple 1,3-addition product with only a trace of side products. The observed reactivity was rationalized with the help of mechanistic calculations performed using density functional theory.
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