Catalysis by Lithium Cation: Lithium Trifluoromethanesulfonate as a Substitute for Lithium Perchlorate in Cycloadditions

doi:10.1055/s-2000-6705

Cited by 3 publications

(2 citation statements)

References 10 publications

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“…Although the acceleration was attributed to “internal pressure” in the original paper, Dailey proposed that it could be explained by the unique Lewis acidity of weakly- or noncoordinated lithium cations in solution, which are recently referred to as “naked” lithium cations . The unique catalysis offered by naked lithium has been employed to promote not only Diels–Alder reactions but a wide variety of chemical transformations. − In 1994, our group found that the ability of the lithium cation to accelerate Diels–Alder reactions was much improved when dissolved in nitromethane (NM), and a LPC/NM system was used as an electrolyte solution for synthetic organic electrochemistry. The first example was the Diels–Alder reactions of unstable quinones ( 16 ), which were generated in situ by anodic SET-oxidation of the corresponding hydroquinones ( 15 ) (Scheme ).…”

Section: Anodic Set-triggered [2 + 2] Cycloadditionsmentioning

confidence: 99%

Redox-Tag Processes: Intramolecular Electron Transfer and Its Broad Relationship to Redox Reactions in General

2017

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Explosive growth in the use of open shell reactivity, including neutral radicals and radical ions, in the field of synthetic organic chemistry has been observed in the past decade, particularly since the advent of ruthenium complexes in 2008. These complexes generally induce single-electron transfer (SET) processes via visible-light absorption. Additionally, recent significant advancements in organic electrochemistry involving SET processes to provide open shell reactivity offer a complementary method to traditional polarity-driven reactions described by two-electron transfer processes. In this Review, we highlight the importance of intramolecular SET processes in the field of synthetic organic chemistry, which seem to be more elusive than the intermolecular versions, since they are net redox-neutral and thus cannot simply be regarded as oxidations or reductions. Such intramolecular SET processes can rationally be understood in combination with concomitant bond formations and/or cleavages, and are regulated by a structural motif that we call a "redox tag." In order to describe modern radical-driven reactions involving SET processes, we focus on a classical formalism in which electrons are treated as particles rather than waves, which offers a practical yet powerful approach to explain and/or predict synthetic outcomes.

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Section: Anodic Set-triggered [2 + 2] Cycloadditionsmentioning

confidence: 99%

Redox-Tag Processes: Intramolecular Electron Transfer and Its Broad Relationship to Redox Reactions in General

2017

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“…Examples for using WCAs in applied chemistry are the lithium(I)-catalyzed reactions [2][3][4][5] as well as transition metal-catalyzed reactions [6][7][8][9] . Applications comprise olefin polymerization 10 and electrochemistry.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and structure of salts of a sterically shielded, lipophilic, C2-symmetric, fluxional aluminate

Söhner¹,

Küppers²,

Wackerow³

et al. 2014

Arkivoc

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Multi-gram amounts of halogen-free lipophilic aluminate salts have been prepared, featuring two sterically demanding chelating ligands derived from a methane-2,2´-bisphenolate. The ligand is prepared by condensation of two equivalents of 2,4-di-tert-butylphenol with acetone induced by boron fluoride etherate. The C 2 -symmetry of this "almebate" anion implies helical chirality. Substantial steric shielding of the aluminate core results in high stability towards aqueous bases. Almebate salts hydrolyze in aqueous acetic acid at room temperature within days. Tetraphenylphosphonium and tetrabutylammonium salts have been prepared by salt metatheses. Sodium almebate can be activated thermally, generating electrophilic sodium(I) with a low coordination number. It eliminates chloride ligands from an N-heterocyclic carbene gold chloride complex, proven by a single-crystal X-ray diffraction study. The barrier of molecular racemization by a degenerate rearrangement of the intrinsically chiral almebate anion in acetone has been determined to be G ‡ 53.6 ± 2 kJ mol -1 from four 1 H NMR coalescence phenomena (500 MHz; 258 K, 273 K, 283 K, 290 K).

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ChemInform Abstract: Catalysis by Lithium Cation: Lithium Trifluoromethanesulfonate as a Substitute for Lithium Perchlorate in Cycloadditions.

Augé¹,

Gil²,

Kalsey³

et al. 2000

ChemInform

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Catalysis by Lithium Cation: Lithium Trifluoromethanesulfonate as a Substitute for Lithium Perchlorate in Cycloadditions

Abstract: Lithium trifluoromethanesulfonate, an easily accessible lithium salt, is shown to be a safe alternative to lithium perchlorate as a promotor in organic Diels-Alder and hetero Diels-Alder reactions.

Cited by 3 publications

References 10 publications

Redox-Tag Processes: Intramolecular Electron Transfer and Its Broad Relationship to Redox Reactions in General

Redox-Tag Processes: Intramolecular Electron Transfer and Its Broad Relationship to Redox Reactions in General

Synthesis and structure of salts of a sterically shielded, lipophilic, C2-symmetric, fluxional aluminate

ChemInform Abstract: Catalysis by Lithium Cation: Lithium Trifluoromethanesulfonate as a Substitute for Lithium Perchlorate in Cycloadditions.

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