Deprotonation of furans using lithium magnesates

Deprotonierende Metallierungen mit 'at‐Verbindungen: Synergie, Synthese und Strukturaufbau

“…Verglichen mit zuvor beschriebenen Lithiumbase-vermittelten Reaktionen [32] [33] Es wurde vermutet, dass Lithiumtrimethylmagnesiat die aktive Spezies in den beobachteten Additionsreaktionen ist. Deprotonierungen gelangen auch, wenn acidere Substrate wie Fluor- [34] und Chlorpyridine [35] Die Reaktionen von Thiophenen [37] und Furanen [38] Reaktionen der Oxazole 29 und 30 (Schema 10) mit Lithiummagnesiaten wurden ausführlich untersucht, wobei insbesondere analysiert wurde, welche Spezies nach dem Deprotonierungsschritt in der Lösung vorliegen. [39] Die 2-Lithiooxazole, die durch Reaktion von Alkyllithiumreagentien mit den Heterocyclen entstehen, werden in Form der bei Raumtemperatur vorherrschenden, offenen Lithium-2-(isocyan)enolate stabilisiert.…”

Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities

“…Recently, a new halogen–magnesium exchange reagent s BuMgOR⋅ x LiOR ( x =1 or 2; R=2‐ethylhexyl) has been developed allowing fast Br/Mg or Cl/Mg exchange reactions producing heteroaryl magnesium alkoxides in non‐polar solvents . Mongin and co‐workers have developed a range of bimetallic ate complexes for the metallation of many functionalised aromatics, combining lithium with a variety of secondary metals including zinc, copper or magnesium . These metallating agents usually consist of a mixed alkyl or amido lithium species with either a divalent metal salt or a dialkyl/amido metallic species.…”

Spectroscopic Advances in Structural Lithium Chemistry: Diffusion‐Ordered Spectroscopy and Solid‐State NMR

“…Hetero bimetallic complexes or ate complexes are considered as the main representatives of this family. These complexes, which are widely used in aromatic substrate deprotonation reactions, include zincates such as LiZntBu 2 (TMP) (TMP, tetramethylpiperidide) [46], Bu 4 MgLi 2 [47], and [(TMEDA)⋅Na(μ-TMP)(μ-tBu)Zn(tBu)] (TMEDA, tetramethylethylenediamine) [48]. Owing to the importance of knowing the true nature in solution of reactive species for understanding reaction mechanisms, several groups have focused on determining the structure of the major members of this family of complexes, by using the DOSY experiment [49].…”