Ultrafast Halogen Dance Reactions of Bromoarenes Enabled by Catalytic Potassium Hexamethyldisilazide

Inoue, Kengo; Mori, Atsunori; Okano, Kentaro

doi:10.1002/chem.202400104

Cited by 3 publications

(1 citation statement)

References 103 publications

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“…We explored potassium aryltrifluoroborates, [24][25][26] which are more widely available than their lithium counterparts. [27] First, the catalytic activities of potassium aryltrifluoroborates 54 and 55 in the halogen dance reaction of 2,3-dibromopyridine (16) were assessed (Scheme 14). Treatment of pyridine 16 and catalyst 54 with LDA and subsequent iodination provided 4iodopyridine 56 and 3-iodopyridine 46 in 3 % and 88 % yields, respectively.…”

Section: Khmds Catalystmentioning

confidence: 99%

Catalytic Approaches to the Halogen Dance Reaction for Molecular Editing

Inoue,

Okano

2024

ChemCatChem

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Transposition reactions, i.e., switching the position of functional groups, are a powerful tool for molecular editing. The transposition of a halogen atom attached to an aromatic ring, referred to as the halogen dance reaction, has great potential in the fields of pharmaceuticals, agrochemicals, natural products, and functional materials. However, the substrate scope of this reaction is limited owing to the intrinsic difficulty in facilitating multiple catalytic cycles involving several aryllithium species. In this concept paper, recent advances in halogen dance catalysis that have expanded the substrate scope of this reaction are highlighted.

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Section: Khmds Catalystmentioning

confidence: 99%

Catalytic Approaches to the Halogen Dance Reaction for Molecular Editing

Inoue,

Okano

2024

ChemCatChem

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Functionalisation of Chromane by Deprotonative Metallation

Bastien,

Erb,

Halauko

et al. 2024

Eur J Org Chem

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Despite the biological interest in chromane derivatives, few studies dedicated to the functionalisation of this heterocycle have been reported. Herein, our objective is to demonstrate the potential of alkali metal bases for the introduction of substituents at its positions 4 and 8, and to explain the observed reactivity based on quantum chemical calculations. Guided by these theoretical results, preliminary optimisation was carried out on 2,3‐dihydrobenzofuran before applying the optimal conditions to chromane. Deprotolithiation at C8 was thus achieved using n‐butyllithium in hexane at room temperature, while functionalisation at C4 was promoted by a 1:1 mixture of lithium 2,2,6,6‐tetramethylpiperidide and potassium tert‐butoxide in tetrahydrofuran at ‐50 °C. Various electrophiles were used to intercept the lithiated intermediates, providing a convenient access to substituted chromane derivatives.

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Potassium Hexamethyldisilazide (KHMDS): Solvent-Dependent Solution Structures

Spivey,

Collum

2024

J. Am. Chem. Soc.

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Solution structures of potassium hexamethyldisilazide [KHMDS] and labeled [ 15 N]KHMDS were examined using a number of analytical methods including 29 Si NMR spectroscopy and density functional theory computations. A combination of 15 N− 29 Si couplings, 29 Si chemical shifts, and the method of continuous variations reveals dimers, monomers, and ion pairs. Weakly coordinating monofunctional ligands such as toluene, N,N-dimethylethylamine, and Et 3 N afford exclusively dimers. 1,3-Dioxolane, THF, dimethoxyethane, hexamethylphosphoramide, and diglyme provide dimers at low ligand concentrations and monomers at high ligand concentrations. N,N,N′,N'-Tetramethylethylenediamine and N,N,N′,N'-tetramethylcyclohexanediamine provide exclusively dimers at all ligand concentrations at ambient temperatures and significant monomer at −80 °C. Studies of 12-crown-4 ran into technical problems. Equimolar 15crown-5 forms a dimer, whereas excess 15-crown-5 affords a putative ion pair. Whereas equimolar 18-crown-6 also affords a dimer, an excess provides a monomer rather than a solvent-separated ion pair. [2.2.2]cryptand affords what is believed to be a contact-ionpaired cryptate. Solvation was probed using largely density functional theory (DFT) computations. Thermally corrected energies are consistent with lower aggregates and higher solvates at low temperatures, but the magnitudes of the computed temperature dependencies were substantially larger than the experimentally derived data.

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Ultrafast Halogen Dance Reactions of Bromoarenes Enabled by Catalytic Potassium Hexamethyldisilazide

Cited by 3 publications

References 103 publications

Catalytic Approaches to the Halogen Dance Reaction for Molecular Editing

Catalytic Approaches to the Halogen Dance Reaction for Molecular Editing

Functionalisation of Chromane by Deprotonative Metallation

Potassium Hexamethyldisilazide (KHMDS): Solvent-Dependent Solution Structures

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