5384-63-4Relevant academic research and scientific papers
Facile Reversible Benzophenone Insertion into Rare-Earth Metal Pyrazolate Complexes
Werner, Daniel,Deacon, Glen B.,Junk, Peter C.,Anwander, Reiner
, p. 3419 - 3428 (2017)
Treatment of the homoleptic CeIV pyrazolate complex [Ce(Me2pz)4]2 (Me2pz = 3,5-dimethylpyrazolato) with benzophenone (bp) led to the formation of an Me2pz-substituted diphenylmethoxy-(N,O)-chelating ligand (pdpm), possibly metal-templated through initial coordination of bp to the cerium atom and subsequent bp insertion into the Ce–N(Me2pz) bond. This coordination/insertion process was shown to be reversible, leading to a complex sequence of equilibria involving multiple degrees of insertion/de-insertion and association/dissociation. The dependency on temperature and the amount of bp of all equilibria was revealed, with insertion/association of bp being favored at low temperatures and de-insertion/dissociation preferentially occurring at elevated temperatures. Such sets of equilibria were also observed for the treatment of trivalent complexes [Ln(Me2pz)3(thf)]2 (Ln = La, Ce, Lu) with bp. Through structural analysis, the trivalent complexes were shown to be less effective in the bp-to-pdpm conversion than the CeIV derivative, giving direct evidence of how an increase in rare-earth Lewis acidity aids in ketone anchorage and concomitant conversion. The observed equilibria seem to also apply to the more illustrious organocerium systems. The conversion of bp into the corresponding tertiary alcohol by the routinely employed reagent CeCl3/nBuLi is the most selective when termination of the reaction by hydrolysis is performed at lower temperatures, with a reagent ratio bp/CeCl3/nBuLi of 1:1:1.
Iron-catalysed 1,2-aryl migration of tertiary azides
Wei, Kaijie,Yang, Tonghao,Chen, Qing,Liang, Siyu,Yu, Wei
, p. 11685 - 11688 (2020/10/19)
1,2-Aryl migration of α,α-diaryl tertiary azides was achieved by using the catalytic system of FeCl2/N-heterocyclic carbene (NHC) SIPr·HCl. The reaction generated aniline products in good yields after one-pot reduction of the migration-resultant imines.
I-Pr2NMgCl·LiCl Enables the Synthesis of Ketones by Direct Addition of Grignard Reagents to Carboxylate Anions
Colas, Kilian,Dos Santos, A. Catarina V. D.,Mendoza, Abraham
supporting information, (2019/10/08)
The direct preparation of ketones from carboxylate anions is greatly limited by the required use of organolithium reagents or activated acyl sources that need to be independently prepared. Herein, a specific magnesium amide additive is used to activate and control the addition of more tolerant Grignard reagents to carboxylate anions. This strategy enables the modular synthesis of ketones from CO2 and the preparation of isotopically labeled pharmaceutical building blocks in a single operation.
Palladium-Catalyzed One-Pot Conversion of Aldehydes and Ketones into 4-Substituted Homopropargyl Alcohols and 5-En-3-yn-1-ols ?
Umana, Christian A.,Cabezas, Jorge A.
, p. 9505 - 9514 (2017/09/23)
Sequential treatment of 2,3-dichloropropene with magnesium and n-BuLi generated the equivalent of 1,3-dilithiopropyne, which adds regiospecifically to aldehydes and ketones to produce homopropargyl alcohols. The lithium acetylide intermediate formed in this protocol can be further reacted with aromatic and vinyl halides, under palladium catalysis, to produce 4-substituted homopropargyl alcohols and 5-en-3-yn-1-ols, respectively, in one-pot with good overall yields.
LITHIUM-POROUS METAL OXIDE COMPOSITIONS AND LITHIUM REAGENT-POROUS METAL COMPOSITIONS
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Paragraph 0057, (2014/10/29)
The invention relates to lithium reagent-porous metal oxide compositions having RLi absorbed into a porous oxide. In formula RLi, R is an alkyl group, an alkenyl group, an alkyny group, an aryl group, an alkaryl group, or an NR1R2 group; R1 is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkaryl group; and R2 is hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and an alkaryl group. The preparation and use of lithium reagent-porous metal oxide compositions having RLi absorbed into a porous oxide compositions are also described.
Introducing deep eutectic solvents to polar organometallic chemistry: Chemoselective addition of organolithium and grignard reagents to ketones in air
Vidal, Cristian,Garcia-Alvarez, Joaquin,Hernan-Gomez, Alberto,Kennedy, Alan R.,Hevia, Eva
supporting information, p. 5969 - 5973 (2014/06/10)
Despite their enormous synthetic relevance, the use of polar organolithium and Grignard reagents is greatly limited by their requirements of low temperatures in order to control their reactivity as well as the need of dry organic solvents and inert atmosphere protocols to avoid their fast decomposition. Breaking new ground on the applications of these commodity organometallics in synthesis under more environmentally friendly conditions, this work introduces deep eutetic solvents (DESs) as a green alternative media to carry out chemoselective additions of ketones in air at room temperature. Comparing their reactivities in DES with those observed in pure water suggest that a kinetic activation of the alkylating reagents is taking place, favoring nucleophilic addition over the competitive hydrolysis, which can be rationalized through formation of halide-rich magnesiate or lithiate species. Turning lithium green: A new protocol for the selective addition of Grignard and organolithium reagents to ketones in green, biorenewable, and deep eutectic solvents (DESs) is reported. The protocol establishes a bridge between main-group organometallic compounds and green solvents (ChCl=choline chloride; see picture). The DESs are superior reaction media for highly polar organometallic compounds.
Copper-catalyzed aerobic aliphatic C-H oxygenation with hydroperoxides
Too, Pei Chui,Tnay, Ya Lin,Chiba, Shunsuke
, p. 1217 - 1225 (2013/07/26)
We report herein Cu-catalyzed aerobic oxygenation of aliphatic C-H bonds with hydroperoxides, which proceeds by 1,5-H radical shift of putative oxygen-centered radicals (O-radicals) derived from hydroperoxides followed by trapping of the resulting carboncentered radicals with molecular oxygen.
Novel alkylidenating agents of iron(III) derivatives by base-mediated α,μ-dehydrohalogenation and their chemical trapping by cycloaddition
Eisch, John J.,Sohn, Jane U.,Rabinowitz, Edon J.
experimental part, p. 2971 - 2977 (2010/08/20)
Studies of the reactions between group 4 metal, chlorides (M = Ti, Zr, Hf) and methyllithium at -78 °C in toluene can lead to methylidene-metal complexes, H2C=MCl2, by a sequence of monomethylation, α-carbon lithiation and α,μ-elimination of LiCl. Here study of the preparation of alkylidene derivatives of iron was attempted by the interaction of FeCl3 with n-butyllithium in various ratios at -78 °C. The presence of any resulting butylidene-iron(III) derivative, nPrCH=FeE (E = Cl, nBu), was probed by adding chemical trapping agents, such as diphenylacetylene, benzonitrile, methyl benzoate and benzophenone. In each experiment the hydrolyzed products were consistent with a cycloaddition reaction of nPrCH=FeE with the trapping agent. The products from, di-phenylacetylene and from, benzonitrile with D2O workup are uniquely in accord with such a carbene precursor. A 3:1 ratio of nBuLi/FeCl3 gave the optimal yield of nPrCH=FenBu, ca. 80%, from, the MBu2FeCl precursor. When a 3:1. reaction mixture was simply brought to 25 °C and hydrolyzed, the purple alkylidene-iron complex decomposed completely to iron metal. A study of a 3:1 interaction of PhCH2MgCl and FeCl3 under similar conditions and trapping with diphenylacetylene provided evidence for the formation of PhCH=FeCH2Ph in ca. 40%. These results support; the hope that alkylidene-iron(III) analogs of the Grubbs reagents may be accessible by this process.
Highly efficient alkylation to ketones and aldimines with Grignard reagents catalyzed by zinc(II) chloride
Hatano, Manabu,Suzuki, Shinji,Ishihara, Kazuaki
, p. 9998 - 9999 (2007/10/03)
A highly efficient alkylation to ketones and aldimines with Grignard reagents in the presence of catalytic trialkylzinc(II) ate complexes derived from ZnCl2 (10 mol %) in situ was developed. This simple Zn(II)-catalyzed alkylation could minimize the well-known but serious problems with the use of only Grignard reagents, which leads to reduction and aldol side products, and the yield of desired alkylation products could be improved. Copyright
Highly alkyl-selective addition to ketones with magnesium ate complexes derived from Gignard reagents
Hatano, Manabu,Matsumura, Tokihiko,Ishihara, Kazuaki
, p. 573 - 576 (2007/10/03)
(Chemical Equation Presented) A highly efficient alkyl-selective addition to ketones with magnesium ate complexes derived from Grignard reagents and alkyllithiums is described. The nucleophilicity of R in R3MgLi is remarkably increased compared to that of the original RLi or RMgX, while the basicity of R3MgLi is decreased. Furthermore, a highly R-selective addition to ketones is demonstrated using RMe2MgLi in place of R 3MgLi.
