Synthesis
DOI: 10.1055/a-2705-6957
Paper
Published as part of the Special Topic Dedicated to Prof. Paul Knochel

Lanthanum(III)-Mediated Dearomative Alkylation of Quinolines

Authors

  • Muzhen Mao

    1   The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
  • Wenwen Lou

    2   Department of Mathematics, Shandong University, Jinan, China
  • Haoer Guna

    1   The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
  • Yi-Hung Chen

    1   The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China

National Natural Science Foundation of China grants 22271221.


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Abstract

We report the lanthanum(III)-mediated dearomative alkylation of quinoline derivatives that enables direct C2-selective functionalization under mild conditions. This single-step protocol utilizes alkyllithium reagents in the presence of LaCl₃•2LiCl and LiAlH₄ to effect regioselective C–C bond formation while simultaneously reducing the quinoline to afford diverse 2-alkyl-substituted tetrahydroquinolines (THQs). The method displays broad substrate scope, tolerating various alkyl groups and heteroaromatic scaffolds, including acridine and quinoxaline. Mechanistic studies support a stepwise C2-alkylation and C3-hydride delivery pathway. Notably, this strategy allows for rapid access to THQ frameworks prevalent in bioactive natural products and pharmaceutical agents. The use of an lanthanide reagent and mild, scalable conditions highlights the practicality of this transformation. This work establishes a versatile approach to THQ synthesis and expands the repertoire of lanthanide-mediated dearomative functionalization.

Supplementary Material



Publication History

Received: 19 July 2025

Accepted after revision: 29 August 2025

Accepted Manuscript online:
19 September 2025

Article published online:
08 October 2025

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