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Robust Cobalt Catalyst for Nitrile/Alkyne [2+2+2] Cycloaddition: Synthesis of Polyarylpyridines and Their Mechanochemical Cyclodehydrogenation to Nitrogen-Containing Polyaromatics*.
Wang, Chang-Sheng; Sun, Qiao; García, Felipe; Wang, Chen; Yoshikai, Naohiko.
Afiliação
  • Wang CS; Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
  • Sun Q; Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
  • García F; Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
  • Wang C; Zhejiang Key Laboratory of Alternative Technologies for Fine Chemical Process, Shaoxing University, Shaoxing, 312000, P. R. China.
  • Yoshikai N; Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Angew Chem Int Ed Engl ; 60(17): 9627-9634, 2021 Apr 19.
Article em En | MEDLINE | ID: mdl-33559370
ABSTRACT
The transition-metal-catalyzed [2+2+2] cycloaddition of nitriles and alkynes is an established synthetic approach to pyridines; however, these cycloadditions often rely on the use of tethered diynes or cyanoalkynes as one of the reactants. Thus, examples of efficient, fully intermolecular catalytic [2+2+2] pyridine synthesis, especially those employing unactivated nitriles and internal alkynes leading to pentasubstituted pyridines, remain scarce. Herein, we report on simple and inexpensive catalytic systems based on cobalt(II) iodide, 1,3-bis(diphenylphosphino)propane, and Zn that promote [2+2+2] cycloaddition of various nitriles and diarylacetylenes for the synthesis of a broad range of polyarylated pyridines. DFT studies support a reaction pathway involving oxidative coupling of two alkynes, insertion of the nitrile into a cobaltacyclopentadiene, and C-N reductive elimination. The resulting tetra- and pentaarylpyridines serve as precursors to hitherto unprecedented nitrogen-containing polycyclic aromatic hydrocarbons via mechanochemically assisted multifold reductive cyclodehydrogenation.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Angew Chem Int Ed Engl Ano de publicação: 2021 Tipo de documento: Article País de afiliação: Singapura

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Angew Chem Int Ed Engl Ano de publicação: 2021 Tipo de documento: Article País de afiliação: Singapura