10.1002/anie.202013153
The study presents a novel chemical protocol for synthesizing symmetrical bis(aryls) by leveraging the synergistic effects between lithium and manganese(II). The researchers utilized a series of organometallic reagents, including lithium manganate [Li2Mn(CH2SiMe3)4] (2b), aryliodides, and alkylating agents like CH2SiMe3. These chemicals served to facilitate a tandem process involving direct Mn-I exchange and oxidative C-C homocoupling. The lithium manganate 2b enabled the efficient Mn-I exchange of aryliodides, producing transient (aryl)lithium manganate intermediates that spontaneously underwent C-C homocoupling at room temperature to yield symmetrical (bis)aryls under mild conditions. The study's purpose was to uncover the reactivity and mechanisms behind these transformations, which were further elucidated through structural and spectroscopic studies on the organometallic intermediates. This work not only advances the understanding of metal-halogen exchange and homocoupling processes but also provides a sustainable route to synthetically relevant symmetrical bis(aryl) molecules.
10.1021/ic990208p
The research focuses on the synthesis and characterization of novel heterometallic lanthanide silsesquioxanes, which are compounds containing both a lanthanide and lithium within their structure. The purpose of this study was to explore the chemistry of rare earth ions in the highly electron-withdrawing environment provided by siloxane ligands, with the expectation of observing novel reactivity such as electrophilic C-H activation. The researchers successfully prepared and characterized the first examples of these heterometallic silsesquioxanes using X-ray diffraction, demonstrating the basicity of the Si-O-Si bridging oxygen atom through its unprecedented coordination to a lithium atom. Key chemicals used in the process included lanthanide tris-silylamides, trisilanol, PMDTA (a type of amine), and various silsesquioxane ligands, such as (C6H11)7Si7O12 and (C6H11)7Si7O11(OSiMe3). The conclusions of the research were that the first stable lithium derivatives of silsesquioxanes had been prepared, and a rare example of a complex where two silsesquioxane cages are bonded to a single central metal atom was achieved.
10.1021/jo00312a034
The research focused on the development of an improved protocol for the cleavage of N-N bonds in N-(methoxycarbonyl)- and N-acetylhydrazines. The purpose of this study was to address the disadvantages of the existing hydrogenation methods over W-2 Raney nickel, which included harsh conditions, potential saturation of aromatic residues, and the inability to cleave certain chiral auxiliaries without causing epimerization. The researchers concluded that lithium in ammonia is an effective reagent for the cleavage of scalemic, monoacylated hydrazines, with complete preservation of configuration on both sides of the hydrazine.
10.1021/acs.joc.5b01136
The research focuses on reductive lithiation, a method for preparing organolithium compounds, typically involving the use of aromatic radical-anions or lithium metal in the presence of an aromatic electron transfer catalyst. The study explores the reductive lithiation of alkyl phenyl thioethers, alkyl chlorides, acrolein diethyl acetal, and isochroman using lithium dispersion as a source of lithium metal, absent of an electron transfer agent. The experiments involved various substrates with different alkyl group sizes to investigate the steric effect on the reaction's efficiency and selectivity. The analyses included DFT calculations to understand the bond dissociation energies and adsorption geometries on the lithium surface, as well as traditional organic chemistry techniques such as NMR spectroscopy and mass spectrometry to characterize the products and monitor the progress of the reactions. The results showed that lithium dispersion could achieve reductive lithiation efficiently and that the reactivity order was reversed when comparing the presence or absence of an electron transfer agent, with smaller alkyl groups exhibiting greater reactivity. This discovery challenges the prevailing understanding of reductive lithiation and highlights the significance of steric effects in these reactions.
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Xi, 
C, 
F
F:Flammable;
