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Erscheinungsjahr
- 2020 (2) (entfernen)
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- Preprint (Vorabdruck) (2) (entfernen)
Sprache
- Englisch (2)
Schlagworte
- Boranes (1)
- Borylene (1)
- Diborene (1)
- boron (1)
- reactive intermediates (1)
- reductive coupling (1)
Institut
- Institut für Anorganische Chemie (2) (entfernen)
EU-Projektnummer / Contract (GA) number
- 669054 (2)
The reductive coupling of an NHC-stabilized aryldibromoborane yields a mixture of trans- and cis-diborenes in which the aryl groups are coplanar with the diborene core. Under dilute reduction conditions two diastereomers of a borirane-borane intermediate are isolated, which upon further reduction give rise to the aforementioned diborene mixture. DFT calculations suggest a mechanism proceeding via nucleophilic attack of a dicoordinate borylene intermediate on the aryl ring and subsequent intramolecular B-B bond formation.
Whereas the reduction of N-heterocyclic carbene (NHC)-stabilised cymantrenyldibromoboranes, (NHC)BBr\(_2\)Cym, in benzene results in formation of the corresponding diborenes (NHC)\(_2\)B\(_2\)Cym\(_2\), a change of solvent to THF yields a borylene of the form (NHC)\(_2\)BCym, stabilised through its boratafulvene resonance form.