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Synlett
DOI: 10.1055/a-2705-9302
Letter

Visible-Light-Induced Ru-Catalyzed Ortho C−H Diarylation of 2-Phenyl-2H-Indazoles and 1-Phenyl-1H-Pyrazoles

Authors

  • Sumit Ghosh 

    1   Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, India
    2   Integrated Science Education & Research Centre, Visva-Bharati (A Central University), Santiniketan, India (Ringgold ID: RIN527357)

  • Asim Kumar Ghosh

    1   Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, India

  • Frenki Mahato

    1   Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, India

  • Abu Taher

    3   Department of Chemistry, Bankura University, Bankura, India

  • Subrata Sinha

    2   Integrated Science Education & Research Centre, Visva-Bharati (A Central University), Santiniketan, India (Ringgold ID: RIN527357)

  • Alakananda Hajra 

    1   Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, India

Funding Information A.H. and A.T. acknowledge the financial support from ARNF, New Delhi (TARE scheme # TAR/2022/000548). We acknowledge FIST, DST for providing S&T support. A.K.G thanks CSIR-SRF for his fellowship.
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Graphical Abstract

Abstract

C–H functionalization is unlocking new avenues in molecular design by transforming the inert carbon–hydrogen bond into a versatile handle for creating complex and value-added compounds with remarkable precision. Taking this into account, we have developed a new ruthenium-catalyzed mild, one-step, robust methodology for ortho C−H diarylation of 2-phenyl-2H-indazoles using aryl iodides as an arylating reagent under photo-mediated conditions at room temperature. This approach extends seamlessly to another heteroarene, 1-phenyl-1H-pyrazole. The strategy shows broad substrate scope, an extensive range of functional group compatibility, and moderate to excellent yield formation. Furthermore, gram-scale synthesis demonstrates the practical applicability of the method.

Keywords

Visible-light-induced transformation - Ortho C−H functionalization - Diarylation - Indazole - Pyrazole - Ru-catalysis

Supplementary Material



Publication History

Received: 27 July 2025

Accepted after revision: 01 September 2025

Accepted Manuscript online:
19 September 2025

Article published online:
05 November 2025

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