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Updated: Oct 3, 2025
Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
Evidence for Borylene Carbonyl (LHB═C═O) and Base-Stabilized (LHB═O) and Base-Free Oxoborane (RB≡O) Intermediates in
Andreas Stoy1,2, Marcel Härterich1,2, Rian D Dewhurst1,2
1Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
Abstract:
Doubly N-heterocyclic-carbene-stabilized diborenes undergo facile reactions with CO2, initially providing dibora-β-lactones. These lactones convert over time to their 2,4-diboraoxetan-3-one isomers through a presumed dissociative pathway and hypovalent boron species borylene carbonyls (LHB═C═O) and base-stabilized oxoboranes (LHB═O). Repeating these reactions with doubly cyclic(alkyl)(amino)carbene-stabilized diborenes allowed the isolation of a borylene carbonyl intermediate, whereas a base-stabilized oxoborane could be inferred by the isolation of a boroxine from the reaction mixture. These results, supported by calculations, confirm the presumed mechanism of the diboralactone-to-diboraoxetanone isomerization while also establishing a surprising level of stability for three unknown or very rare hypovalent boron species: base-stabilized derivatives of the parent borylene carbonyl (LHB═C═O) and parent oxoborane (LHB═O) as well as base-free oxoboranes (RB≡O).
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