Ortholithiation of Anisole by <i>n</i>-BuLi−TMEDA:  Reaction via Disolvated Dimers

Rennels, Roger A.; Maliakal, and Ashok J.; Collum, David B.

doi:10.1021/ja972610d

Cited by 66 publications

(70 citation statements)

References 19 publications

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“…Metalation of [ 15 N 4 ] 3 with two equiv of recrystallized [ 6 Li] n -BuLi 21 in THF at −78 °C was incomplete, affording lithium amide- n -BuLi (see below) and unreacted diamine 3 . 22-24 Subsequent warming to −20 °C for 10 min caused complete consumption of 3 , affording dilithiated amide homoaggregate 4 as a complex mixture that was not investigated further.…”

Section: Resultsmentioning

confidence: 99%

“…Lithiation of [ 15 N 4 ] 3 with ≥3.0 equiv of [ 6 Li]BuLi 21 in 6.1 M THF/hexane affords a dilithium amide- n -BuLi mixed aggregate displaying three 6 Li resonances (1:1:1) along with resonances of residual n -BuLi dimer and tetramer 26 at elevated n -BuLi concentrations (Figures 2 and 3). The resonance count and intensities, most easily observed in the 15 N broadband decoupled spectrum (Figure 2A), are consistent with those of trilithiated mixed aggregate 6 or the corresponding dimerized hexalithiated 5 observed crystallographically.…”

Section: Resultsmentioning

confidence: 99%

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Enediolate–Dilithium Amide Mixed Aggregates in the Enantioselective Alkylation of Arylacetic Acids: Structural Studies and a Stereochemical Model

Stivala

Wright

et al. 2013

J. Am. Chem. Soc.

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A combination of X-ray crystallography, 6Li, 15N, and 13C NMR spectroscopies, and density functional theory computations afford insight into the structures and reactivities of intervening aggregates underlying highly selective asymmetric alkylations of carboxylic acid dianions (enediolates) mediated by the dilithium salt of a C2-symmetric chiral tetraamine. Crystallography shows a trilithiated n-butyllithium-dilithiated amide that has dimerized to a hexalithiated form. Spectroscopic studies implicate the non-dimerized trilithiated mixed aggregate. Reaction of the dilithiated amide with phenylacetic acid with excess n-butyllithium affords a tetralithio aggregate comprised of the two dianions in solution and the dimerized octalithio form in the solid state. Computational studies shed light on the details of the solution structures and afford a highly predictive stereochemical model.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Enediolate–Dilithium Amide Mixed Aggregates in the Enantioselective Alkylation of Arylacetic Acids: Structural Studies and a Stereochemical Model

Stivala

Wright

et al. 2013

J. Am. Chem. Soc.

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“…The hexane contained 1% tetraglyme to dissolve the ketyl. Both n -BuLi and LDA were recrystallized 6,7. Solutions of n -BuLi and LDA were titrated using a literature method 18.…”

Section: Methodsmentioning

confidence: 99%

Lithium Diisopropylamide-Mediated Ortholithiations: Lithium Chloride Catalysis

et al. 2009

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Ortholithiations of a range of arenes mediated by lithium diisopropylamide (LDA) in THF at -78 °C reveal substantial accelerations by as little as 0.5 mol % LiCl (relative to LDA). Substrate dependencies suggest a specific range of reactivity within which the LiCl catalysis is optimal. Standard protocols using unpurified commercial samples of n-butyllithium to prepare LDA or commercially available LDA show marked batch-dependent rates--up to 100-fold--that could prove significant to the unwary practitioner. Other lithium salts elicit more modest accelerations. The mechanism is not discussed.

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“…Polymerizations with the initiator systems containing p-xylene, 4,4′ -dimethylbiphenyl, and di-p-tolylmethane were also investigated. KEY WORDS Living Anionic Polymerization / Polystyrene / Initiation Reaction / Lithiation / Anion Transfer Reaction / (Received June 12, 2007: Accepted September 10,2007) [ Kobunshi Ronbunshu, 64(12), 943-948 (2007)]…”

Section: Living Anionic Polymerization Of Styrene With Initiation Reamentioning

confidence: 99%

Living Anionic Polymerization of Styrene with Initiation Reactions Involving Anion Transfer Reactions

Goto¹,

Ujino²,

Okai³

et al. 2007

KOBUNSHI RONBUNSHU

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Ortholithiation of Anisole by n-BuLi−TMEDA: Reaction via Disolvated Dimers

Cited by 66 publications

References 19 publications

Enediolate–Dilithium Amide Mixed Aggregates in the Enantioselective Alkylation of Arylacetic Acids: Structural Studies and a Stereochemical Model

Enediolate–Dilithium Amide Mixed Aggregates in the Enantioselective Alkylation of Arylacetic Acids: Structural Studies and a Stereochemical Model

Lithium Diisopropylamide-Mediated Ortholithiations: Lithium Chloride Catalysis

Living Anionic Polymerization of Styrene with Initiation Reactions Involving Anion Transfer Reactions

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