Borylation Directed Borylation of Indoles Using Pyrazabole Electrophiles: A One-Pot Route to C7-Borylated-Indolines

Jürgen Pahl, Emily Noone, Marina Uzelac, Kang Yuan, Michael J. Ingleson

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7 Citations (SciVal)


Pyrazabole (1) is a readily accessible diboron compound that can be transformed into ditopic electrophiles. In 1 (and derivatives), the B⋅⋅⋅B separation is ca. 3 Å, appropriate for one boron centre bonding to N and one to the C7 of indoles and indolines. This suitable B⋅⋅⋅B separation enables double E−H (E=N/C) functionalisation of indoles and indolines. Specifically, the activation of 1 with HNTf2 generates an electrophile that transforms N−H indoles and indolines into N/C7-diborylated indolines, with N−H borylation directing subsequent C7−H borylation. Indole reduction to indoline occurs before C−H borylation and our studies indicate this proceeds via hydroboration—C3-protodeboronation to produce an intermediate that then undergoes C7 borylation. The borylated products can be converted in situ into C7-BPin-N-H-indolines. Overall, this represents a transient directed C−H borylation to form useful C7-BPin-indolines.

Original languageEnglish
Article numbere202206230
JournalAngewandte Chemie - International Edition
Issue number32
Publication statusPublished - 8 Aug 2022


  • Boranes
  • C−H Borylation
  • Electrophilic Substitution
  • Indoles
  • Transient Directing Group

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)


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