An Improved Procedure for the Preparation of Organolithium Compounds

Gilman, Henry; Zoellner, E. A.; Selby, W. M.

doi:10.1021/ja01344a033

Cited by 65 publications

(20 citation statements)

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“…[20] Some solvents were dried by distillation over the appropriate drying agent under argon. The melting points were measured on a B¸chi SMP-20 apparatus.…”

Section: Methodsmentioning

confidence: 99%

“…General: All commercial chemicals were used as received without further purification, nBuLi solution was titrated by the double titration method described by Gilman and al. [20] 6 )-e À ) 2 ). 6 ] 2 as a mixture of endo/exo conformers: 1-[PF 6 ] 2 (0.050 g, 0.0425 mmol) and 2 (0.032 g, 0.050 mmol) were dissolved in ethylene glycol (5 mL) and refluxed under argon for 4 h at 140 8C.…”

Section: Methodsmentioning

confidence: 99%

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Templated Synthesis of a Rotaxane with a [Ru(diimine)₃]²⁺ Core

Pomeranc

Jouvenot

Chambron

et al. 2003

Chemistry A European J

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A rotaxane containing a ruthenium bisphenanthroline complex, acting as an axis, and a macrocycle incorporating a 2,2'-bipyridine (bpy) unit, threaded by the axis, has been synthesized. The bisphenanthroline ligand is such that its ruthenium(II) complexes possess a clearly identified axis, making such compounds ideal components of rotaxanes constructed around an octahedral ruthenium(II) center, which serves as a template. The ring is threaded by the axial ruthenium(II) precursor complex, to afford the corresponding pseudorotaxane in moderate yield. The X-ray structure analysis of this compound reveals the threaded nature of the complex. The length of the threaded ring (35 atoms in the periphery) is too short to allow easy threading of the axis through the macrocycle. As a consequence, an isomer is also obtained for which the axial ruthenium complex is attached in an exo fashion. (1)H NMR studies have been carried out, which reveal various conformational equilibria for the pseudorotaxane. Light-induced decoordination of the bpy-containing cyclic fragment was shown to be quantitative and to lead to the free ring and the axial ruthenium(II) complex, regardless of the starting compound (pseudorotaxane or exo isomer). Finally, the real rotaxane could be prepared, although it could not be separated from its exo isomer.

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“…[20] Some solvents were dried by distillation over the appropriate drying agent under argon. The melting points were measured on a B¸chi SMP-20 apparatus.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Templated Synthesis of a Rotaxane with a [Ru(diimine)₃]²⁺ Core

Pomeranc

Jouvenot

Chambron

et al. 2003

Chemistry A European J

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“…Best results were achieved when alkyl chlorides were used in alkanes or benzene, but also alkyl bromides and solutions in ether provided satisfactory results. Wittig and Gilman modified and improved the syntheses very successfully.…”

Section: Organolithium Compoundsmentioning

confidence: 99%

200 Years of Lithium and 100 Years of Organolithium Chemistry

Wietelmann

Klett

2018

Zeitschrift anorg allge chemie

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The element lithium has been discovered 200 years ago. Due to its unique properties it has emerged to play a vital role in industry, esp. for energy storage, and lithium‐based products and processes support sustainable technological developments. In addition to the many uses of lithium in its inorganic forms, lithium has a rich organometallic chemistry. The development of organometallic chemistry has been hindered by synthetic problems from the start. When Wilhelm Schlenk developed the basic principles to handle and synthesize air‐ and moisture‐sensitive compounds, the road was open to further developments. After more information was available about the stability and solubility of such compounds, they started to play an essential role in other fields of chemistry as alkyl or aryl transfer reagents.

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“…47 PhLi and p-tolyllithium− lithium bromide were prepared according to known procedures. 48,49 The coordinated diethyl ether was removed under vacuum, and the residue was recrystallized from THP. Synthesis of [(p-bromophenyl)CaI(THP) 4 ] (3).…”

Section: ■ Conclusionmentioning

confidence: 99%

Arylcalcium Iodides in Tetrahydropyran: Solution Stability in Comparison to Aryllithium Reagents

et al. 2012

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Reduction of para-substituted iodobenzene in tetrahydropyran (THP) with finely dispersed calcium powder yields arylcalcium iodides of the type [(THP) 4 Ca(C 6 H 4 -4-R)I] with R = CH 3 (1), Cl (2), Br (3), I (4), OCH 3 (5). A 2-fold insertion of calcium into dihalobenzenes was not observed. The β-naphthylcalcium iodide [(THP) 4 Ca(β-Naph)I] (6) is also accessible by direct synthesis in THP. The durability of arylcalcium compounds in THP was studied in comparison to that in THF, and a slightly enhanced lifetime in THP at ambient temperature was observed. Furthermore, the relative reactivity and selectivity of 1 and its lithium counterpart [{(THP) 2 Li} 2 (μ-Tol)(μ-Br)] (7) in the reaction with THP and THF were studied. α-Metalation and subsequent cycloreversion was the major pathway observed for THF in both cases. In the degradation reaction induced by 7, several byproducts arising from carbolithiation and, surprisingly, from β-metalation reactions were identified, while 1 was found to be more selective. The related [(THP) 2 Li(μ-Ph)] 2 (9) was prepared and used to unambiguously identify some of the products. In order to verify the formation of benzyllithium as one of the byproducts, an authentic sample of [(dme)Li(μ-CH 2 Ph] 2 (8) was prepared. In THP, an inversion of the relative reactivity of 1 and 7 was observed and the calcium compound was found to be more reactive than its lithium analogue. The crystal structures of 1−9 were determined by X-ray diffraction studies, and a trans arrangement of the anionic ligands due to electrostatic reasons was observed in case of the hexacoordinated calcium complexes. ■ INTRODUCTIONThe year 2005 marked the occurrence of the first structurally characterized arylcalcium derivatives, independently prepared by the groups of Niemeyer, 1 Harder, 2 and Westerhausen, 3 using different synthetic strategies. During the following years arylcalcium derivates emerged from elusive academic curiosities to an easily accessible group of substances. 4 These compounds show tremendous potential and might be able to challenge the well-established aryllithium derivatives in organic and organometallic syntheses. The worldwide accessibility of calcium, its low price, and its nontoxic behavior regardless of concentration further encourage subsequent investigations. Given its position in the periodic table, the alkaline-earth metal calcium is expected to combine typical properties of s block metals (saltlike behavior, highly heteropolar metal−carbon bonds) and early transition metals (Lewis acidity of cations, d orbital participation, and catalytic activity) within its compounds. Considering a few preconditions, convenient high-yield syntheses of solutions of these post-Grignard reagents have been developed recently. 5 These preconditions are as follows:(i) Activation of calcium succeeds with ammonia, yielding a finely divided highly reactive metal powder. (ii) The direct synthesis has to be performed in ethereal solutions, preferably in THF.(iii) Iodoarenes represent the most suitable substrates; br...

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An Improved Procedure for the Preparation of Organolithium Compounds

Cited by 65 publications

References 0 publications

Templated Synthesis of a Rotaxane with a [Ru(diimine)₃]²⁺ Core

Templated Synthesis of a Rotaxane with a [Ru(diimine)₃]²⁺ Core

200 Years of Lithium and 100 Years of Organolithium Chemistry

Arylcalcium Iodides in Tetrahydropyran: Solution Stability in Comparison to Aryllithium Reagents

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An Improved Procedure for the Preparation of Organolithium Compounds

Cited by 65 publications

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Templated Synthesis of a Rotaxane with a [Ru(diimine)3]2+ Core

Templated Synthesis of a Rotaxane with a [Ru(diimine)3]2+ Core

200 Years of Lithium and 100 Years of Organolithium Chemistry

Arylcalcium Iodides in Tetrahydropyran: Solution Stability in Comparison to Aryllithium Reagents

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Product

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Templated Synthesis of a Rotaxane with a [Ru(diimine)₃]²⁺ Core

Templated Synthesis of a Rotaxane with a [Ru(diimine)₃]²⁺ Core