Ruthenium- and rhodium-catalyzed direct carbonylation of the ortho C-H bond in the benzene ring of N-arylpyrazoles

Taku Asaumi, Takuya Matsuo, Takahide Fukuyama, Yutaka Ie, Fumitoshi Kakiuchi, Naoto Chatani

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)

Abstract

The direct carbonylation of C-H bonds in the benzene ring of N-phenylpyrazoles via catalysis by ruthenium or rhodium complexes is described. The reaction of N-phenylpyrazoles with carbon monoxide and ethylene in the presence of Ru3(CO)12 or Rh4(CO)12 resulted in the site-selective carbonylation of the ortho C-H bonds in the benzene ring to give the corresponding ethyl ketones. A variety of functional groups on the benzene ring can be tolerated. N-Phenylpyrazoles have higher reactivities than would be expected, based on the pKa values of the conjugate acid of pyrazole. The choice of solvent for this reaction is significant, and N, N-dimethylacetamide (DMA) gives the best result.

Original languageEnglish
Pages (from-to)4433-4440
Number of pages8
JournalJournal of Organic Chemistry
Volume69
Issue number13
DOIs
Publication statusPublished - 2004 Jun 25
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry

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