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Expedient syntheses of the N-heterocyclic carbene precursor imidazolium salts IPr.HCl, IMes.HCl and IXy.HCl.

ABSTRACT: The 1,3-diaryl-imidazolium chlorides IPr.HCl (aryl = 2,6-diisopropylphenyl), IMes.HCl (aryl = 2,4,6-trimethylphenyl) and IXy.HCl (aryl = 2,6-dimethylphenyl), precursors to widely used N-heterocyclic carbene (NHC) ligands and catalysts, were prepared in high yields (81%, 69% and 89%, respectively) by the reaction of 1,4-diaryl-1, 4-diazabutadienes, paraformaldehyde and chlorotrimethylsilane in dilute ethyl acetate solution. A reaction mechanism involving a 1,5-dipolar electrocyclization is proposed.

SUBMITTER: Hintermann L

PROVIDER: S-EPMC2151073 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature

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Expedient syntheses of the N-heterocyclic carbene precursor imidazolium salts IPr.HCl, IMes.HCl and IXy.HCl.

Hintermann Lukas L

Beilstein journal of organic chemistry 20070828

The 1,3-diaryl-imidazolium chlorides IPr.HCl (aryl = 2,6-diisopropylphenyl), IMes.HCl (aryl = 2,4,6-trimethylphenyl) and IXy.HCl (aryl = 2,6-dimethylphenyl), precursors to widely used N-heterocyclic carbene (NHC) ligands and catalysts, were prepared in high yields (81%, 69% and 89%, respectively) by the reaction of 1,4-diaryl-1, 4-diazabutadienes, paraformaldehyde and chlorotrimethylsilane in dilute ethyl acetate solution. A reaction mechanism involving a 1,5-dipolar electrocyclization is propos ...[more]

PMID: 17725838

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