Synthesis of methylene-bridge polyarenes through palladium-catalyzed activation of benzylic carbon-hydrogen bond

Chien Chi Hsiao, Yi Kuan Lin, Chia Ju Liu, Tsun Cheng Wu, Yao Ting Wu

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

In the presence of palladium(II) acetate [Pd(OAc)2] and an N-heterocyclic carbene (NHC) ligand, fluorene derivatives can be generated in good to excellent yields from 2-halo-2′-methylbiaryls through the benzylic C-H bond activation (14 examples; 81-97% yields). The scope and limitations of this protocol have been examined. A wide range of functional groups, such as alkyl, alkoxy, ester, nitrile, and others, is able to tolerate the reaction conditions herein. The cyclization of an isotope-labelled biphenyl gave the corresponding product with a primary kinetic isotope effect (k H/kD=4.8:1), which indicates that the rate-determining step of this reaction is the activation of the benzylic C-H bond. Moreover, indenofluorenes were also accessed in excellent results from terphenyls (3 examples; 91-92% yields). The cascade reaction of 2,6-dichloro-2′- methylbiphenyl with diphenylacetylene produced 8,9-diphenyl-4H-cyclopenta[def] phenanthrene in 60% yield through the activation of an aryl and a benzylic C-H bond.

Original languageEnglish
Pages (from-to)3267-3274
Number of pages8
JournalAdvanced Synthesis and Catalysis
Volume352
Issue number18
DOIs
Publication statusPublished - 2010 Dec 17

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

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