Catalyst-free hydroboration of CO2 with a nucleophilic diborane(4)
Hydroboration generally requires the presence of a catalyst to lower the barrier for hydride transfer. This work reports on the first catalyst-free CO2 hydroboration with a neutral boron compound, the nucleophilic diborane [HB(hpp)]2, 1 (hpp=1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate). Fur...
Gespeichert in:
| Hauptverfasser: | , , , |
|---|---|
| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
11 September 2018
|
| In: |
Chemistry - a European journal
Year: 2018, Jahrgang: 24, Heft: 64, Pages: 16983-16986 |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201804612 |
| Online-Zugang: | Verlag, Volltext: https://doi.org/10.1002/chem.201804612 Verlag, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201804612 
|
| Verfasserangaben: | Markus Frick, Julian Horn, Hubert Wadepohl, Elisabeth Kaifer, and Hans-Jörg Himmel |
| Zusammenfassung: | Hydroboration generally requires the presence of a catalyst to lower the barrier for hydride transfer. This work reports on the first catalyst-free CO2 hydroboration with a neutral boron compound, the nucleophilic diborane [HB(hpp)]2, 1 (hpp=1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate). Further hydroboration reactions to bis(boryl)acetals are possible. In acetonitrile, but not in dichloromethane solutions, hydroboration of a first CO2 is followed by hydroboration of a second CO2 molecule. Detailed kinetic measurements for both hydroboration steps were carried out and the influence of the solvent and the addition of a Lewis base on the rate constants analyzed. In contrast to catalyst-free hydroboration of CO2, hydroboration of the less electrophilic acetone requires the presence of an activating Lewis acid. |
|---|---|
| Beschreibung: | Im Titel ist „2“ tiefgestellt Gesehen am 24.07.2019 |
| Beschreibung: | Online Resource |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201804612 |