Expedient synthesis of E-hydrazone esters and 1H-indazole scaffolds through heterogeneous single-atom platinum catalysis

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Cuibo Liu
  • Zhongxin Chen
  • Huan Yan
  • Shibo Xi
  • Kah Meng Yam
  • Jiajian Gao
  • Yonghua Du
  • Jing Li
  • Xiaoxu Zhao
  • Keyu Xie
  • Haisen Xu
  • Kai Leng
  • Stephen J. Pennycook
  • Chun Zhang
  • Ming Joo Koh
  • Kian Ping Loh

Detail(s)

Original languageEnglish
Article numbereaay1537
Journal / PublicationScience Advances
Volume5
Issue number12
Online published6 Dec 2019
Publication statusPublished - 6 Dec 2019
Externally publishedYes

Link(s)

Abstract

Unprotected E-hydrazone esters are prized building blocks for the preparation of 1H-indazoles and countless other N-containing biologically active molecules. Despite previous advances, efficient and stereoselective synthesis of these compounds remains nontrivial. Here, we show that Pt single atoms anchored on defect-rich CeO2 nanorods (Pt1/CeO2), in conjunction with the alcoholysis of ammonia borane, promotes exceptionally E-selective hydrogenation of α-diazoesters to afford a wide assortment of N-H hydrazone esters with an overall turnover frequency of up to 566 hours−1 upon reaction completion. The α-diazoester substrates could be generated in situ from readily available carboxylic esters in one-pot hydrogenation reaction. Utility is demonstrated through concise, scalable synthesis of 1H-indazole–derived pharmaceuticals and their 15N-labeled analogs. The present protocol highlights a key mechanistic nuance wherein simultaneous coordination of a Pt site with the diazo N=N and ester carbonyl motifs plays a central role in controlling stereoselectivity, which is supported by density functional theory calculations. Copyright © 2019 The Authors, some rights reserved.

Research Area(s)

Citation Format(s)

Expedient synthesis of E-hydrazone esters and 1H-indazole scaffolds through heterogeneous single-atom platinum catalysis. / Liu, Cuibo; Chen, Zhongxin; Yan, Huan et al.
In: Science Advances, Vol. 5, No. 12, eaay1537, 06.12.2019.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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