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Synthesis
DOI: 10.1055/a-2733-4012
Paper
Published as part of the Special Issue in Honor of Prof. Franziska Schoenebeck, the 2025 Women in Chemistry Award Winner

Photocatalytic Regioselective Hydroboration of Indoles and Benzofurans with N-Heterocyclic Carbene Boranes

Authors

  • Yubing Pang

    1   State Key Laboratory of Synergistic Chem-Bio Synthesis and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China (Ringgold ID: RIN12474)

  • Zongyang Ma

    1   State Key Laboratory of Synergistic Chem-Bio Synthesis and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China (Ringgold ID: RIN12474)
    2   Inner Mongolia Key Laboratory of Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, China (Ringgold ID: RIN12576)

  • Juntao Ye

    1   State Key Laboratory of Synergistic Chem-Bio Synthesis and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China (Ringgold ID: RIN12474)

Financial support from the National Natural Science Foundation of China (grant no. 22371180) is acknowledged.
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Graphical Abstract

Dedication

Dedicated to Professor Franziska Schoenebeck on the occasion of her being awarded the 2025 Women in Chemistry Award.

Abstract

Dearomative hydroboration of arenes using nucleophilic boryl radicals provides a powerful strategy for converting flat, abundant arenes into valuable, three-dimensional organoboron architectures. While such reactions are well established for electron-deficient arenes, the analogous transformation of electron-rich heteroarenes remains challenging due to a polarity mismatch. Herein, we report a photocatalytic approach that enables the regioselective, dearomative hydroboration of both electron-rich and electron-deficient indoles and benzofurans using N-heterocyclic carbene boranes. Density functional theory calculations indicate that the C2 addition of the boryl radical is kinetically favored over the C3 addition, and that the addition step becomes irreversible due to a subsequent, low-barrier hydrogen-atom-transfer event.

Keywords

Photocatalysis - Boryl radical - Hydroboration - Dearomatization - Organoboron - N-heterocyclic carbene borane

Supplementary Material



Publication History

Received: 22 September 2025

Accepted after revision: 27 October 2025

Accepted Manuscript online:
27 October 2025

Article published online:
19 November 2025

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