Synthesis and characterization of dialkylaluminum arylimine complexes

Kingsley, Nicholas B.; Doyon, Tyler; Shephard, Logan E.

doi:10.1016/j.jorganchem.2015.10.026

Cited by 6 publications

(8 citation statements)

References 48 publications

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“…In the case of iso-indolinones,a"head-to-head" intermolecularn ucleophilic addition can occur to give species II (Scheme5 ), which can then undergo af urtheri ntramolecular addition, resulting in ar ing-closing step to yield species III (Scheme 5). The elimination of lithium hydride (LiH) results in the formation of iso-indolinimine IV (Scheme 5), which upon work-upu ndergoes hydrolysis to the desired iso-indolinone (7).…”

Section: Resultsmentioning

confidence: 99%

“…NMR spectra were recorded on aB ruker AVANCE DRX 400 spectrometer operating at 400.13 MHz for 1 H, 100.62 MHz for 13 Ca nd 155.5 MHz for 7 Li. All 13 Cs pectra were proton decoupled.…”

Section: Generalc Onsiderationsmentioning

confidence: 99%

“…Recent studies from Tang, Kingsley and Dostál have shown that this approach can generate ortho ‐lithiated aryl imines in situ . These can be further functionalised to give new aluminium, titanium and benzaborole compounds by using simple metathesis pathways, and iso ‐indolinones from CO insertion followed by cyclisation (Scheme ). However, insight into the structural composition of the lithium intermediates have, to date, not been crystallographically determined.…”

Section: Introductionmentioning

confidence: 99%

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Lithium–Bromide Exchange versus Nucleophilic Addition of Schiff's base: Unprecedented Tandem Cyclisation Pathways

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Andrews

et al. 2019

Chemistry A European J

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By exploring lithium–bromide exchange reactivity of aromatic Schiff's bases with tert‐butyllithium (tBuLi), we have revealed unprecedented competitive intermolecular and intramolecular cascade annulation pathways, leading to valuable compounds, such as iso‐indolinones and N‐substituted anthracene derivatives. A series of reaction parameters were probed, including solvent, stoichiometry, sterics and organolithium reagent choice, in order to understand the influences that limit such ring‐closing pathways. With two viable reactivity options for the organolithium on the imine; namely, nucleophilic addition or lithium–bromide exchange, a surprising competitive nature was observed, where nucleophilic addition dominated, even under cryogenic conditions. Considering the most commonly used solvents for lithium–bromide exchange, tetrahydrofuran (THF) and diethyl ether (Et2O), contrasting reactivity outcomes were revealed with nucleophilic addition promoted in THF, while Et2O yielded almost double the conversion of cyclic products than in THF.

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Section: Resultsmentioning

confidence: 99%

“…NMR spectra were recorded on aB ruker AVANCE DRX 400 spectrometer operating at 400.13 MHz for 1 H, 100.62 MHz for 13 Ca nd 155.5 MHz for 7 Li. All 13 Cs pectra were proton decoupled.…”

Section: Generalc Onsiderationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lithium–Bromide Exchange versus Nucleophilic Addition of Schiff's base: Unprecedented Tandem Cyclisation Pathways

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Andrews

et al. 2019

Chemistry A European J

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“…This lengthy route is probably the reason why 2‐iminomethylphenyltellurium species ( VI ) are less frequently described in the literature than other intramolecularly coordinated tellurium compounds ( I – V ) that are more readily available. Recently, 2‐iminomethylphenyl‐supported compounds of group 13, group 14, group 15, and the lighter group 16 elements, were prepared by the ortho ‐directed lithiation route, which prompted us to develop similar synthetic protocols also for tellurium species containing 2‐( tert ‐butyliminomethyl)phenyl‐ and 2‐(2′,6′‐diisopropylphenyliminomethyl)phenyltellurium species ( VI , Scheme ). Five archetypal tellurium compounds were prepared and fully characterized by heteronuclear NMR spectroscopy and X‐ray crystallography.…”

Section: Introductionmentioning

confidence: 99%

Intramolecularly Coordinated 2‐Iminomethylphenyltellurium Compounds

et al. 2017

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Procedures for the synthesis of 2-(tBuNCH)-C 6 H 4 Te(S 2 CNEt 2 ) (1a), 2-(2′,6′-iPr 2 C 6 H 3 NCH)C 6 H 4 Te(S 2 CNEt 2 ) (1b), [2-(tBuNCH)C 6 H 4 ] 2 Te (2a), 2-(tBuNCH)C 6 H 4 TeCl (3a), and 2-(tBuNCH)C 6 H 4 TeCl 3 (4a) have been developed. Compounds 1a-4a possess 2-iminomethylphenyl groups that provide intramolecular N donation to the Te atoms, which was investigated by multinuclear NMR spectroscopy and X-ray crystallography. The Te-N bond lengths increase in the order 3a [2.203 (2) Å] < 4a [2.286(1) Å] < 1b [2.337(2) Å] < 1a [2.407(2) Å] < 2a [a] 3435 Scheme 1. Tellurium compounds stabilized by intramolecular N(sp 3 ) donation (top row) and N(sp 2 ) donation (bottom row). Full PaperScheme 2. General route for the synthesis of 2-iminomethylphenyltellurium compounds reported in the literature. analyzed through DFT calculations and real-space bonding indicators (RSBI), which are derived from the computed electron and pair densities. Topological dissection of the electron density (ED) according to the atoms-in-molecules (AIM) space-partitioning scheme [88] provides a bond-path motif that resembles the molecular structure as well as details of atomic properties such as charges and volumes. Analysis of the reduced density gradient, s(r) = [1/2(3π 2 ) 1/3 ]|∇ρ|/ρ 4/3 , according to the recently introduced noncovalent interactions (NCI) index [89] affords noncovalent bonding aspects. Notably, the assignment of different contact types, including steric/repulsive (λ 2 > 0), van der Waals like (λ 2 ≈ 0), and attractive (λ 2 < 0) interactions is facilitated by mapping the product of the ED and the sign of the second eigenvalue of the Hessian [sign(λ 2 )ρ] on the isosurfaces of s(r). Finally, topological dissection of the pair density according to the electron localizability indicator (ELI-D) [90] provides core, bonding, and lone-pair basins, which are especially valuable for the analysis of covalent (including dative) bonds. ELI-D isosurfaces (localization domain representations of the basins) and NCI isosurfaces show a complementary spatial distribution, [91] which suggests spatial separation of covalent and noncovalent bonding aspects, which has been a matter of recent debate. [92] The combination of AIM, NCI, and ELI-D thus allows the monitoring of minute electronic changes in the Te-N interaction, which is dominated by covalent bonding aspects for short Te-N distances and ionic bonding aspects for longer Te-N distances. These calculations extend previous computational studies on intramolecularly coordinated N-donor tellurium compounds by us [93] and others. [94,95] Scheme 3. Synthesis of 1a-4a and 1b.

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“…These stabilised precursors have been further used in the synthesis of Group 13 heterocycles via an addition and cyclisation pathway (see section 4.1 forimine addition/cyclisation). Kingsley and co-workerse xtended this synthetic strategy in 2016 [59] to access as eries of mono-ligateda ryl-imine dialkylaluminiumc omplexes (Scheme 17). The imine functionalityp lays av ital role providing intramolecular stabilisation for these dialkylaluminium aryl-imine complexes that are being tested as potentialpolymerisation catalysts.…”

Section: Metathesismentioning

confidence: 99%

Main Group Metal‐Mediated Transformations of Imines

Orr

Andrews

Blair

2020

Chemistry A European J

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Main‐group‐metal‐mediated transformations of imines have earned a valued place in the synthetic chemist's toolbox. Their versatility allows the simple preparation of various nitrogen containing compounds. This review will outline the early discoveries including metallation, addition/cyclisation and metathesis pathways, followed by the modern‐day use of imines in synthetic methodology. Recent advances in imine C−F activation protocols are discussed, alongside revisiting “classic” imine reactivity from a sustainable perspective. Developments in catalytic methods for hydroelementation of imines have been reviewed, highlighting the importance of s‐block metals in the catalytic arena. Whilst stoichiometric transformations in alternative reaction media such as deep eutectic solvents or water have been summarised. The incorporation of imines into flow chemistry has received recent attention and is summarised within.

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Synthesis and characterization of dialkylaluminum arylimine complexes

Cited by 6 publications

References 48 publications

Lithium–Bromide Exchange versus Nucleophilic Addition of Schiff's base: Unprecedented Tandem Cyclisation Pathways

Lithium–Bromide Exchange versus Nucleophilic Addition of Schiff's base: Unprecedented Tandem Cyclisation Pathways

Intramolecularly Coordinated 2‐Iminomethylphenyltellurium Compounds

Main Group Metal‐Mediated Transformations of Imines

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