Insights into the Metalation of Benzene and Toluene by Schlosser’s Base: A Superbasic Cluster Comprising PhK, PhLi, and tBuOLi

Abstract

The metalation of benzene by Schlosser's base (nBuLi/tBuOK) occurs smoothly in THF at low temperatures to afford a discrete mixed-metal Li2 K4 cluster that contains phenyl anions and tert-butoxide. The aggregate itself exhibits superbasic behavior by metalating toluene. The delocalized benzyl anion obtained this way π bonds to potassium counterions, thereby creating a 2D coordination polymer.

[Bis(Trimethylsilyl)Methyl]Lithium and -Sodium: Solubility in Alkanes and Complexes with O- and N- Donor Ligands

“…Due to the one-sided interaction of the lithium with the bis(trimethylsilyl)methyl group, the (Me 3 Si) 2 According to X-ray crystallographic data the sodium compound 2a ( Figure 5) organizes in the solid state as a polymeric chain along the crystallographic b-axis consisting of THF-coordinated 2 units with sodium oxygen-interactions (Na1-O1 2.375(3) Å). The central carbon of the CH(SiMe 3 ) 2 group shows a roughly linear (Na-C-Na 159.30 (18) • ) coordination by two sodium atoms with slightly different bond lengths (Na1-C1 2.778(4) Å; Na1A-C1 2.657(4) Å), leading to an approximately trigonal bipyramidal environment of the carbon atom. A very similar pattern of Na-C distances was found in polymeric TMEDA-coordinated trimethylsilylmethylsodium with Na-C 2.523 Å and 2.530 Å [8].…”

“…Complexes formed by coordination of 1 with TMEDA or PMDETA were also isolated (1-TMEDA (1b) and 1-PMDETA), and the solid state structure of 1-PMDETA revealed monomeric units [16]. The understanding of the solution behavior of alkali metal alkyl compounds will allow insights into more complicated systems such as Lochmann-Schlosser superbases [17,18]. Recently, we reported the preparation of neopentyl potassium [KCH 2 tBu], which small but existing solubility allowed us to identify corresponding mixed lithium/potassium neopentyl/tert-butoxide aggregates [19] with possible relevance for such superbasic systems.…”

Towards the Next Generation of Lochmann–Schlosser Superbases: A Potassium Neopentyl/Alkoxy Aggregate used in the Tetra‐Functionalization of Ferrocene

“…[1a,c] The experimental problems caused by the insolubility and fierce reactivity make it even more important to study simpler compounds instead. [12] The latter two compounds could demonstrate their basicity towards toluene. Very instructivee xamples were found in the homometallic 1:1 combination of lithium t-butoxide and n-butyllithium [Li 8 (nBu) 4 (OtBu) 4 ], [8] and the bimetallic 1:1c ombination of lithium t-butoxide and potassium t-butoxide [Li 4 K 4 (OtBu) 8 ], 1.…”

Die Reaktion von Neopentyllithium mit Kalium‐tert‐butoxid: Bildung einer alkanlöslichen Lochmann‐Schlosser‐Superbase

“…Ein anderes Modell für LS ist eine kristalline,t etramere 1:1-Mischung aus LiOtBu und KOtBu: [Li 4 K 4 (OtBu) 8 ](1). [23] Die Isolierung und strukturelle Charakterisierung des Produktes einer Metallierung von Benzol mit LS in THF durch Strohmann et al ergab [Li 2 K 4 (OtBu)Ph 5 (THF) 6 ], [24] das dimetallisch ist und auch die für LS erwarteten Metall-Sauerstoff-und Metall-Kohlenstoff-Wechselwirkungen aufweist. [21] Weitere Beispiele finden sich in der intramolekularen Kombination von Phenoxy-und Alkylgruppen [22] oder einer superbasischen Amido/Alkoxy-Verbindung.…”

“…[21] Weitere Beispiele finden sich in der intramolekularen Kombination von Phenoxy-und Alkylgruppen [22] oder einer superbasischen Amido/Alkoxy-Verbindung. [ [24] das dimetallisch ist und auch die für LS erwarteten Metall-Sauerstoff-und Metall-Kohlenstoff-Wechselwirkungen aufweist.…”