Pattathil V, Pranckevicius C. Aromaticity transfer in an annulated 1,4,2-diazaborole: facile access to
Cs symmetric 1,4,2,5-diazadiborinines.
Chem Commun (Camb) 2024;
60:7705-7708. [PMID:
38975792 DOI:
10.1039/d4cc02414a]
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Abstract
A tricyclic annulated 1,4,2-diazaborole is readily accessed via reaction of a bidentate pyridyl-carbene ligand with MesBBr2 followed by reduction. Dearomatization of the flanking rings is shown to increase reactivity of this heterocycle in the form of a B-centred alkylation with MeI. Its reaction with hydrido-, fluoro-, and chloro-boranes reveal an unprecedented ring expansion reaction to form a diverse family of B2C2N2 heterocycles, reduction of which allows facile access to the first examples of Cs symmetric 1,4,2,5-diazadiborinines. DFT calculations have shed light on the electronic structures of the reduced species and provide insight into mechanistic aspects of the observed ring-expansion.
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