Dilithium tribenzylidenemethane-2-TMEDA: the first x-ray structure of a Y-conjugated trimethylenemethane dianion derivative

Wilhelm, Dieter; Dietrich, Hans; Clark, Timothy; Mahdi, Waruno; Kos, Alexander J.; Schleyer, Paul v. R.

doi:10.1021/ja00335a088

Cited by 22 publications

(7 citation statements)

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“…Another phenomenon to be taken into account is the hybridization of all the benzylic carbons (about sp 2.5 ), which implies a strong pyramidalization of these carbons, thus making the two H-2 protons of dianion 2 non-equivalent in any possible conformation. MNDO calculations 6 on 1 and the X-ray structure of 1-2TMEDA (2Li ϩ ) 9 show that 1 should exist in a most stable propeller-like conformation (support for this conformation is found in the dynamic behaviour of the methyl groups of 2). Assuming that 2 does not vary much (as is the case with the other properties), this conformation should distinguish one H-2 proton from the other.…”

Section: Mementioning

confidence: 93%

Aryl-substituted derivatives of trimethylenemethane dianion: a dynamic NMR study

Shenhar¹,

Rabinovitz²

1997

J. Chem. Soc., Perkin Trans. 2

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Section: Mementioning

confidence: 93%

Aryl-substituted derivatives of trimethylenemethane dianion: a dynamic NMR study

Shenhar¹,

Rabinovitz²

1997

J. Chem. Soc., Perkin Trans. 2

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“…There Wilhelm et al, 1984), cyclopentadienyl sodium tetramethylethylenediamine (CPNATM10; Aoyagi et al, 1979).…”

Section: Database Surveymentioning

confidence: 99%

Crystal structure of N,N,N′,N′-tetramethylethanediamine

2022

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The title compound N,N,N′,N′-tetramethylethanediamine, C6H16N2, is a bidentate amine ligand commonly used in organolithium chemistry for deaggregation. Crystals were grown at 243 K from n-pentane solution. The complete molecule is generated by a crystallographic center of symmetry and the conformation of the diamine is antiperiplanar. To investigate the intermolecular interactions, a Hirshfeld surface analysis was performed. It showed that H...H (van der Waals) interactions dominate with a contact percentage of 92.3%.

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“…However, the calculated pyramidalization of the terminal carbon atoms in the gas phase without counterions found by Frenking has never been observed experimentally. All X-ray structures of Y-conjugated dianions show planar Y-frameworks. , However, the ligand TMEDA ( N,N,N‘,N‘ -tetramethyl-1,2-ethylenediamine) as well as the lithium cations undoubtedly influence the structures strongly.…”

Section: Introductionmentioning

confidence: 99%

Reactions of the Lithium Salts of the Tribenzylidenemethane Dianion, Diphenylacetone Dianion, and Related Compounds

et al. 1998

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Potentially synthetically useful reactions of the dilithium salts of the title dianions have been investigated. Electrophilic quenching with a variety of reagents usually leads to the expected products in good yield. Quenching the diphenylacetone dianion with 1 equiv of trimethylchlorosilane, however, gives a good yield of 1,3-diphenylallene obtained by formal elimination of a trimethylsiloxy anion from an intermediate monoquenched monoanion salt. NMR studies, however, do not reveal the intermediacy of the 1,3-diphenyl-2-(trimethylsiloxy)allyl anion but rather suggest that the initial reaction site is at carbon, rather than oxygen. Oxidation of the dianions leads either to ring closure or dimerization for the tribenzylidenemethane dianion and to dimerization for the diphenylacetone dianion. The dimerization reactions are stereospecific, both with respect to the two new stereocenters produced and for the double bonds of the bis-silyl enol ether products if the dimeric bis-enolate dianion products are quenched with trimethylchlorosilane.

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Dilithium tribenzylidenemethane-2-TMEDA: the first x-ray structure of a Y-conjugated trimethylenemethane dianion derivative

Cited by 22 publications

References 0 publications

Aryl-substituted derivatives of trimethylenemethane dianion: a dynamic NMR study

Aryl-substituted derivatives of trimethylenemethane dianion: a dynamic NMR study

Crystal structure of N,N,N′,N′-tetramethylethanediamine

Reactions of the Lithium Salts of the Tribenzylidenemethane Dianion, Diphenylacetone Dianion, and Related Compounds

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