Unique Reactivity of Cyclic (Alkyl)(Amino)Carbene Stabilized Acyclic Imino Olefin (AIO) Towards Dinitrogen Transfer Reagent

03 January 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


N-Heterocyclic olefins (NHOs) represent a class of zwitterionic compounds known for their effective electron donor properties, often surpassing those of N-heterocyclic carbenes (NHCs). The properties of NHOs can be significantly fine-tuned by altering both the steric and electronic characteristics around the NHO framework. Parallel to NHOs, N-heterocyclic imines (NHIs) also exhibit exceptional donor properties and act as super-nucleophiles due to the strong ylidic nature of their exocyclic imine moiety. In this study, we employed the cyclic alkyl amino carbene (CAAC)-stabilized NHI to isolate a robust electron-donating acyclic olefin system and showcase its unique reactivity in comparison to traditional NHOs. Moreover, compound 2 shows air and moisture stability. In addition, compound 2 shows thermal stability up to 306 °C under an inert atmosphere. Furthermore, the calculated proton affinity of this compound is 269.9 kcal/mol, akin to the high proton affinities of NHOs reported in the literature. The reactivity of compound 2 with highly nucleophilic dinitrogen transfer azide resulted in four different compounds 3-6 by varying the stoichiometric ratios. Compound 3 is an azo-bridged AIO dimer, while compound 5 features a tetrazolium moiety. Compounds 4 and 6 contain unprecedented nitrogen-containing heterocycles.


Electron rich olefins • Carbenes • NHOs • Tetrazole • Quinoidal tetrazine


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