Phase-transfer-catalysed synthesis of pyrroloindolines and pyridoindolines by a hydrogen-bond-assisted isocyanide cyclization cascade

Peter C. Knipe, Matija Gredičak, Artiom Cernijenko, Robert S. Paton, Martin D. Smith

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

A cascade reaction that generates pyrrolo- and pyridoindoline motifs from isocyanide precursors under phase-transfer conditions is described. This transformation proceeds at room temperature in the presence of a quaternary ammonium catalyst and base to generate functionalized products containing an all-carbon quaternary stereocentre. Quantum chemical calculations demonstrated that intramolecular general acid catalysis plays a key accelerating role through stabilization of developing charge in the transition state, and that the reaction is best described as a 5-endo dig cyclization, rather than an anionic 6π electrocyclization. Investigations employing chiral phase-transfer catalysts have given promising selectivities to date.

LanguageEnglish
Pages3005-3009
Number of pages5
JournalChemistry - A European Journal
Volume20
Issue number11
Early online date12 Feb 2014
DOIs
Publication statusPublished - 10 Mar 2014
Externally publishedYes

Fingerprint

Cyclization
Cyanides
Hydrogen bonds
Catalysts
Catalyst selectivity
Ammonium Compounds
Catalysis
Carbon
Stabilization
Acids
Temperature

Keywords

  • cascade reactions
  • density functional calculations
  • heterocycles
  • hydrogen bonds
  • isocyanides
  • phase-transfer catalysis

Cite this

Knipe, Peter C. ; Gredičak, Matija ; Cernijenko, Artiom ; Paton, Robert S. ; Smith, Martin D. / Phase-transfer-catalysed synthesis of pyrroloindolines and pyridoindolines by a hydrogen-bond-assisted isocyanide cyclization cascade. In: Chemistry - A European Journal. 2014 ; Vol. 20, No. 11. pp. 3005-3009.
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Phase-transfer-catalysed synthesis of pyrroloindolines and pyridoindolines by a hydrogen-bond-assisted isocyanide cyclization cascade. / Knipe, Peter C.; Gredičak, Matija; Cernijenko, Artiom; Paton, Robert S.; Smith, Martin D.

In: Chemistry - A European Journal, Vol. 20, No. 11, 10.03.2014, p. 3005-3009.

Research output: Contribution to journalArticle

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T1 - Phase-transfer-catalysed synthesis of pyrroloindolines and pyridoindolines by a hydrogen-bond-assisted isocyanide cyclization cascade

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AU - Gredičak, Matija

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AU - Paton, Robert S.

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AB - A cascade reaction that generates pyrrolo- and pyridoindoline motifs from isocyanide precursors under phase-transfer conditions is described. This transformation proceeds at room temperature in the presence of a quaternary ammonium catalyst and base to generate functionalized products containing an all-carbon quaternary stereocentre. Quantum chemical calculations demonstrated that intramolecular general acid catalysis plays a key accelerating role through stabilization of developing charge in the transition state, and that the reaction is best described as a 5-endo dig cyclization, rather than an anionic 6π electrocyclization. Investigations employing chiral phase-transfer catalysts have given promising selectivities to date.

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KW - density functional calculations

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