Chemoselectivity in the microwave-assisted solvent-free solid-liquid phase benzylation of phenols: O- versus C-alkylation

G. Keglevich, Erika Bálint, Éva Karsai, A. Grün, Mária Bálint, István Greiner

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The outcome of the solvent-free benzylation of phenol and 4-substituted phenols (such as 4-cresol and 4-chlorophenol) under MW irradiation was found to depend on the absence or presence of the base (K2CO3) and catalyst (triethylbenzylammonium chloride (TEBAC)). Reaction of benzyl halides at 80-120 °C in the presence of K2CO3 and TEBAC resulted in O-alkylation in high (89-96%) chemoselectivities. In the absence of TEBAC, the proportion of C-alkylation was considerable (16-34%). Omitting also K2CO3 from the reaction mixture, C-alkylation became predominant. In the case of 4-tert-butylphenol, the presence of TEBAC promoted C-alkylation. The selectivity of the alkylations can be fine-tuned by choosing the appropriate conditions.

Original languageEnglish
Pages (from-to)5039-5042
Number of pages4
JournalTetrahedron Letters
Volume49
Issue number34
DOIs
Publication statusPublished - Aug 18 2008

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Phenols
Alkylation
Microwaves
Chlorides
Liquids
Phenol
Irradiation
Catalysts
potassium carbonate

Keywords

  • Alkylation
  • Microwave heating
  • Phase transfer catalysis
  • Selectivity

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery

Cite this

Chemoselectivity in the microwave-assisted solvent-free solid-liquid phase benzylation of phenols : O- versus C-alkylation. / Keglevich, G.; Bálint, Erika; Karsai, Éva; Grün, A.; Bálint, Mária; Greiner, István.

In: Tetrahedron Letters, Vol. 49, No. 34, 18.08.2008, p. 5039-5042.

Research output: Contribution to journalArticle

Keglevich, G. ; Bálint, Erika ; Karsai, Éva ; Grün, A. ; Bálint, Mária ; Greiner, István. / Chemoselectivity in the microwave-assisted solvent-free solid-liquid phase benzylation of phenols : O- versus C-alkylation. In: Tetrahedron Letters. 2008 ; Vol. 49, No. 34. pp. 5039-5042.
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