Selektive Spaltung von aromatischen Methylethern mit Lithiumiodid in Chinolin

Kirschke, Klaus; Wolff, Erich

doi:10.1002/prac.19953370186

Cited by 8 publications

(2 citation statements)

References 3 publications

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“…However, the reaction of A‐4 c and B‐4 c with BBr 3 at low temperatures (0 or −80 °C) [20] gave a complex mixture of products, presumably including partially brominated boron clusters. Other demethylation protocols, such as dry LiCl/DMF [21] (80 or 150 °C, 12 h), LiI/quinoline [22] (180 °C, 12 h) and HBr/AcOH [23] (120 °C, 2d) were ineffective and no reaction was observed. Therefore, the protecting group was changed from methyl to benzyl.…”

Section: Resultsmentioning

confidence: 99%

C(1)‐Phenethyl Derivatives of [closo‐1‐CB₁₁H₁₂]⁻ and [closo‐1‐CB₉H₁₀]⁻ Anions: Difunctional Building Blocks for Molecular Materials

Jakubowski

Pietrzak

Friedli

et al. 2020

Chemistry A European J

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C(1)-vinylation of [closo-1-CB 9 H 10 ] À (A)a nd [closo-1-CB 11 H 12 ] À (B)w ith 4-benzyloxystyryl iodide followed by hydrogenationo ft he double bond and reductive deprotection of the phenol functionality led to C(1)-(4-hydroxyphenethyl) derivatives. The phenol functionality was protected as the acetate. The esters weret hen treated with PhI(OAc) 2 and the resulting isomers were separated kinetically (for derivatives of anion A)o rb yc hromatography (for derivatives of anion B)g iving the difunctionalized buildingb locks in overall yields of 9% and 50 %, respectively.Asimilars eries of reactions was performed starting with anions A and B and 4-methoxystyryl bromide and iodide. Significant differences in the reactivity of derivatives of the two carborane anionswere rationalized with DFT computational results. Application of the difunctionalized carboranes as building blocksw as demonstratedt hrough preparation of two ionic liquid crystals. The extensive synthetic work is accompanied by single crystal XRD analysiso fs ix derivatives.

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Section: Resultsmentioning

confidence: 99%

C(1)‐Phenethyl Derivatives of [closo‐1‐CB₁₁H₁₂]⁻ and [closo‐1‐CB₉H₁₀]⁻ Anions: Difunctional Building Blocks for Molecular Materials

Jakubowski

Pietrzak

Friedli

et al. 2020

Chemistry A European J

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“…HBr (48%), 3 TMSI,4 TMSCl-NaI, 5 ]. The second group spans nonacidic but strongly nucleophilic reagents such as NaSEt, 15 NaSPr, 16 sodium benzylselenide, 17 sodium p-thiocresolate, 18 LiCl-DMF, 19 MeMgI, 20 LiI-quinoline, 21 LiI-collidine, 22 NaCN-DMSO, 23 lithium diphenylphosphide, 24 Na 2 S-NMP, 25 MeSLi, 26 n-BuSLi, 27 Me 3 SiSNa 28 or imidazolium or pyridinium salt based ionic liquids. 29 Also, combinations of an acidic and a nucleophilic reagent have been successfully employed (MeSO 3 H-methionine, 30 AlBr 3 -EtSH, 31 AlBr 3 -NaI, 32 and AlCl 3 -EtSH 33 ).…”

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confidence: 99%

Microwave-Assisted Cleavage of Aryl Methyl Ethers with Lithium Thioethoxide (LiSEt)

Cvengroš¹,

Neufeind²,

Becker³

et al. 2008

Synlett

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Lithium thioethoxide (LiSEt), a white solid easily prepared from EtSH and n-BuLi in hexane, was identified as a highly efficient reagent for the cleavage (O-demethylation) of aryl methyl ethers, i.e. methyl-protected phenols. Of particular synthetic value are applications in the double deprotection of 1,2-dimethoxyarenes (to give catechols) and in the selective monodeprotection of di-and trimethoxyarenes. The thermal reactions, which are usually performed in DMF as a solvent, can be greatly accelerated through microwave irradiation. In this case, the monodemethylated products are usually formed in high (80-99%) yield within only 15 minutes.

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Protection for Phenols and Catechols

Wuts

Greene²

2006

Greene's Protective Groups in Organic Synthesis

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Selektive Spaltung von aromatischen Methylethern mit Lithiumiodid in Chinolin

Cited by 8 publications

References 3 publications

C(1)‐Phenethyl Derivatives of [closo‐1‐CB₁₁H₁₂]⁻ and [closo‐1‐CB₉H₁₀]⁻ Anions: Difunctional Building Blocks for Molecular Materials

C(1)‐Phenethyl Derivatives of [closo‐1‐CB₁₁H₁₂]⁻ and [closo‐1‐CB₉H₁₀]⁻ Anions: Difunctional Building Blocks for Molecular Materials

Microwave-Assisted Cleavage of Aryl Methyl Ethers with Lithium Thioethoxide (LiSEt)

Protection for Phenols and Catechols

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Selektive Spaltung von aromatischen Methylethern mit Lithiumiodid in Chinolin

Cited by 8 publications

References 3 publications

C(1)‐Phenethyl Derivatives of [closo‐1‐CB11H12]− and [closo‐1‐CB9H10]− Anions: Difunctional Building Blocks for Molecular Materials

C(1)‐Phenethyl Derivatives of [closo‐1‐CB11H12]− and [closo‐1‐CB9H10]− Anions: Difunctional Building Blocks for Molecular Materials

Microwave-Assisted Cleavage of Aryl Methyl Ethers with Lithium Thioethoxide (LiSEt)

Protection for Phenols and Catechols

Contact Info

Product

Resources

About

C(1)‐Phenethyl Derivatives of [closo‐1‐CB₁₁H₁₂]⁻ and [closo‐1‐CB₉H₁₀]⁻ Anions: Difunctional Building Blocks for Molecular Materials

C(1)‐Phenethyl Derivatives of [closo‐1‐CB₁₁H₁₂]⁻ and [closo‐1‐CB₉H₁₀]⁻ Anions: Difunctional Building Blocks for Molecular Materials