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Updated: May 25, 2025
A Protocol for Safe Lithiation Reactions Using Organolithium Reagents
Published on: November 12, 2016
Lithium Anionic Dicarbenes or Acetylides: What is in the Name?
Arne Merschel1, Henric Steffenfauseweh1, Yury V Vishnevskiy1
1Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615, Bielefeld, Germany.
Abstract:
The two-fold deprotonation of the C2-arylated 1,3-imidazolium salts (IPr-Ar)X (1-Ar)X (IPr-Ar = ArC{N(Dipp)CH}2; Ar = Ph, 4-Me2NC6H4 (DMP) or 4-PhC6H4 (Bp); Dipp = 2,6-iPr2C6H3) with nBuLi affords the so-called anionic dicarbenes Li(ADC) (2-Ar) (ADC = ArC{N(Dipp)C}2). 2-Ar can be used to prepare a variety of main group heterocycles, however their structures in the solid-state remained hitherto unknown. Herein reported single-crystal X-ray diffraction studies reveal an acetylide type [ArC{N(Dipp)}(Dipp)NC≡CLi)]n (3-Ar) dimeric (n = 2) or trimeric (n = 3) molecular structure for 2-Ar. Treatment of 3-Ph with Et3B cleanly yields the monoanionic carbene Li[(ADC)(BEt3)] (4-Ph) featuring a weakly coordinating anion embedded in the same molecular entity. 3-Ar readily undergo reactions with CO2 and N2O to form the ring-closing products Li[(ADC)(CO2)2] (5-Ar) and Li[(ADC)N2O] (6-Ar), respectively.
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