Diversity-Oriented Synthesis of Spiropentadiene Pyrazolones and 1 H-Oxepino[2,3- c]pyrazoles from Doubly Conjugated Pyrazolones via Intramolecular Wittig Reaction

Pankaj V. Khairnar, Chi Yi Wu, Yi Fang Lin, Athukuri Edukondalu, Yi Ru Chen, Wenwei Lin

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

An efficient method for the diversity-oriented synthesis of spiropentadiene pyrazolones and 1H-oxepino[2,3-c]pyrazoles is reported. The methodology attributes O-acylation of phosphorus zwitterions which were formed by a tandem phospha-1,6-addition of PBu3 to α,β,γ,δ-unsaturated pyrazolones, further generating betaine intermediates that preferentially resulted in the aforementioned cyclic products in a diversity-oriented manner. The mechanistic investigations revealed that formation of the betaines is the key step to provide the products via an intramolecular Wittig reaction or an unprecedented δ-C-acylation/cyclization/Wittig reaction.

Original languageEnglish
Pages (from-to)4760-4765
Number of pages6
JournalOrganic Letters
Volume22
Issue number12
DOIs
Publication statusPublished - 2020 Jun 19

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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