Gold-Catalyzed Bicyclic and [3+2]-Annulations of Internal Propargyl Alcohols with Nitrones and Imines To Yield to Two Distinct Heterocycles

Sayaji Arjun More, Tzu Hsuan Chao, Mu Jeng Cheng, Rai Shung Liu

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1 Citation (Scopus)

Abstract

A gold-catalyzed synthesis of 1,3-dihydrooxazolo[3,4-a]indoles from 1-oxo-3-yn-4-ols and nitrones is described; this new bicyclic annulation presents the first examples that internal alkynes can react with nitrones to undergo an oxoarylation route. DFT calculations indicate a [3,3]-sigmatropic shift of initial alkenylgold intermediates to elude the intermediacy of gold carbenes. We also developed new [3+2]-annulations of the same 1-oxo-3-yn-4-ols with imines, yielding oxazolidin-4-ylidene derivatives efficiently. The tethered alcohols of these 1-oxo-3-ynes allow trapping of their metastable 2-azadienium intermediates to enable a novel annulation. Our mechanistic analysis indicates that the two products, despite their structural relevance, are produced from two independent systems. (Figure presented.).

Original languageEnglish
Pages (from-to)525-531
Number of pages7
JournalAdvanced Synthesis and Catalysis
Volume363
Issue number2
DOIs
Publication statusPublished - 2021 Jan 19

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

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