New Methodologies Based on Arene-Catalyzed Lithiation Reactions and Their Application to Synthetic Organic Chemistry

Abstract

The applications of arene‐catalyzed lithiation reactions during recent years are reviewed. This methodology has been used to obtain functionalized organolithium compounds from halogenated as well as nonhalogenated materials, such as heterocycles, sulfones, triflates, ethers, thioethers, amides, and esters. This arene‐catalyzed lithiation has also been used in the preparation of polylithiated intermediates. Sub‐stoichiometric amounts of the arene may be supported on a polymeric material, its catalytic activity being as efficient as in the solution version.

Degradation Mechanism and Enhanced Stability of Organolithium for Chemical Lithiation

“…Liquid samples were injected into a sealed glass capillary (5 mm in diameter) and tested from 3450 to 3650 G with 0.02 mW microwave power, 60.18 s sweep time, 2.00 G modulation amplitude, 100 kHz modulation frequency, and 30 dB receiver gain. 3) 13 C NMR spectra and 7 Li NMR spectra of degraded Li-Bp-2MT were tested using an NMR spectrometer (Bruker AVANCE 600) equipped with a Broad Band Inverse (BBI) probe operating at 600.13 MHz and 298.0 K. 4) Conductivity measurements of the LASs were carried out in an Ar-filled glove box using a conductivity meter (METTLER TOLEDO FiveEasy Plus FE38 with LE703 electrode).…”

“…These chemical shifts then move back to the higher field and finally to the pristine state during aging. Accordingly, in the 7 Li NMR spectra (Figure 2f), a chemical shift appears at 9.4 ppm for 13 C NMR spectra and f) 7 Li NMR spectra of Li-Bp-2MT solutions at various aging times.…”

“…d) EPR spectra. e)13 C NMR spectra and f)7 Li NMR spectra of Li-Bp-2MT solutions at various aging times.…”

“…Among various OLis, Li‐arene solutions (LASs) stand out because of their potential commercial availability and their unique combination of alkaline, nucleophilic, and reducing properties. [ 7 ] Depending on the arene types and ether solvents, the redox potentials of LASs can be finely adjusted from 0.08 to 1.2 V (vs Li + /Li), [ 8 ] making them promising for chemically lithiating conventional electrode materials to provide additional Li resources and increase the cycling life span. [ 8a,9 ] For example, prelithiating a graphite‐SiO x composite (Gr/SiO x ) anode with 0.2 mol L −1 lithium biphenyl in a tetrahydropyran (Li‐Bp‐THP) solution significantly enhanced the reversible energy density of the NCM532 (LiNi 0.5 Co 0.3 Mn 0.2 O 2 )||Gr/SiO x full cell, approaching the theoretical value and achieving a 40% increase compared to the bare material.…”

Trapping of Transient Organolithium Compounds

“…The reaction requires two equivalents of Li metal to complete the reaction, which proceeds through the SET mechanism. Lithium naphthalenide (LN), lithium 1‐(dimethylamino)naphthalenide (LDMAN), and lithium 4,4′‐di‐ tert ‐butylbiphenylide (LDBB) are utilized as electron carriers . Specifically, LDBB is a superior reagent to provide organolithium species by preventing an undesired coupling of the generated radical species R .…”