Schlenk‐Type Equilibria of Grignard‐Analogous Arylberyllium Complexes: Steric Effects**
Abstract
The presence of complex Schlenk equilibria is a central property of synthetically invaluable Grignard reagents substantially affecting their reactivity and selectivity in chemical transformations. In this work, the steric effects of aryl substituents on the Schlenk‐type equilibria of their lighter congeners, arylberyllium bromides, are systematically studied. Combination of diarylberyllium complexes Ar2Be(OEt2) (1Ar, Ar=Tip, Tcpp; Tip=2,4,6‐iPr3C6H3, Tcpp=2,4,6‐Cyp3C6H3, Cyp=c‐C5H9), containing sterically demanding aryl groups, and BeBr2(OEt2)2 (2) affords the Grignard‐analogous arylberyllium bromides ArBeBr(OEt2) (3Ar, Ar=Tip, Tcpp). In contrast, Mes2Be(OEt2) (1Mes, Mes=2,4,6‐Me3C6H3) and 2 exist in a temperature‐dependent equilibrium with MesBeBr(OEt2) (3Mes) and free OEt2. Ph2Be(OEt2) (1Ph) reacts with 2 to afford dimeric [PhBeBr(OEt2)]2 ([3Ph]2). Moreover, the influence of replacing the OEt2 donor by an N‐heterocyclic carbene, IPr2Me2 (IPr2Me2=C(iPrNCMe)2), on the redistribution reactions was investigated. The solution‐ and solid‐state structures of the diarylberyllium and arylberyllium bromide complexes were comprehensively characterized using multinuclear (1H, 9Be, 13C) NMR spectroscopic methods and single‐crystal X‐ray diffraction, while DFT calculations were employed to support the experimental findings.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 15, 2023
- Source ID
- 10.1002/chem.202302222
Entities
People
- Cameron Jones
- Christoph Helling
Organizations
- Air Force Office of Scientific Research
- Alexander von Humboldt Foundation
- Australian Research Council
- Monash University