Nickel-catalyzed, cascade cycloadditions of 1-ethynyl-8-halonaphthalenes with nitriles: Synthesis, structure, and physical properties of new pyrroloarenes

Tsun Cheng Wu, Chia Cheng Tai, Hsin Chieh Tiao, Ming Yu Kuo, Yao Ting Wu

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Abstract

The reaction of 1-ethynyl-8-halonaphthalenes 1 with nitriles in the presence of the catalytic system [NiBr2(dppe)]/Zn (dppe=1,2-bis(diphenylphosphino)ethane) is found to produce unusual pyrroloarenes 2. The carbon-nitrogen triple bond in nitrile is activated twice, and five new bonds are formed in a one-pot transformation, which causes a pyrrole and two six-membered rings to be generated simultaneously. The scope and limitations of this reaction are examined. Similarly, alkyl-bridged diynes also furnish the corresponding polycycles. Diaryl-substituted cycloadducts 2 (R 1=Ar) are fluxional, because of the restriction in rotation of the aryl groups. The rotational barrier is studied by performing 1Ha NMR experiments at various temperatures. The structures of several compounds are determined by X-ray crystallographic analysis. The photophysical and electrochemical properties of the pyrroloarenes are also investigated. (Ni)triles and tribulations: The reaction of 1-ethynyl-8-halonaphthalenes 1 with nitriles in the presence of the catalytic system [NiBr2(dppe)]/Zn (dppe=1,2-bis(diphenylphosphino)ethane) produces unusual pyrroloarenes 2, which have unusual structures (see scheme) and exhibit interesting physical properties. The diluted solutions of these pyrroloarenes are strongly fluorescent, even under ambient light.

Original languageEnglish
Pages (from-to)1930-1935
Number of pages6
JournalChemistry - A European Journal
Volume17
Issue number6
DOIs
Publication statusPublished - 2011 Dec 7

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All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

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