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<p>Asymmetric synthesis of <i>N</i>-<i>N</i> array heterocycles via palladium-catalyzed rapid construction of C(sp<sup>3</sup>)–N and C(sp<sup>3</sup>)–C(sp<sup>2</sup>) remains a formidable challenge. Herein, we demonstrate the β,<i>γ</i>-unsaturated hydrazones with aryl or alkenyl halides leading to a series of dihydropyrazoles in good yields with excellent enantioselectivities. This robust catalyst system is responsible for excellent reactivity and avoiding the <i>N</i>-Ts-hydrazones decomposition. The salient of this transformation include mild reaction conditions, broad substrate scopes, well functional group tolerance. Density functional theory (DFT) calculations disclose the effective coordination mode of palladium/Xu-Phos in asymmetric coupling and shed some light on the reaction mechanism and the origin of the enantioselectivity. Moreover, mechanistic experiments and DFT calculations demonstrate that <i>syn</i>- and <i>anti</i>-additions occur almost simultaneously in the enantiodetermining olefin insertion step.</p>

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Enantioselective synthesis of dihydropyrazoles bearing quaternary stereocenter by palladium/XuPhos-catalyzed tandem reaction: scope and mechanistic insights

  • 期刊论文

  • 发表日期：

    2025年8月26日

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  • Cangzhu Hu,
  • Feifei Jin,
  • Qianqian Hu,
  • Jing Sun,
  • Ying Han,
  • Chaoshen Zhang,
  • Liejin Zhou,
  • Junliang Zhang,
  • Lei Wang

摘要

Asymmetric synthesis of N-N array heterocycles via palladium-catalyzed rapid construction of C(sp3)–N and C(sp3)–C(sp2) remains a formidable challenge. Herein, we demonstrate the β,γ-unsaturated hydrazones with aryl or alkenyl halides leading to a series of dihydropyrazoles in good yields with excellent enantioselectivities. This robust catalyst system is responsible for excellent reactivity and avoiding the N-Ts-hydrazones decomposition. The salient of this transformation include mild reaction conditions, broad substrate scopes, well functional group tolerance. Density functional theory (DFT) calculations disclose the effective coordination mode of palladium/Xu-Phos in asymmetric coupling and shed some light on the reaction mechanism and the origin of the enantioselectivity. Moreover, mechanistic experiments and DFT calculations demonstrate that syn- and anti-additions occur almost simultaneously in the enantiodetermining olefin insertion step.