One-pot synthesis of five- or six-membered carbocycles through intramolecular cycloadditions by the use of ethyl chloroformate

Ju Tsung Liu, Wen Wei Lin, Jeong Jiunn Jang, Jing Yuan Liu, Ming Chung Yan, Chihua Hung, Kuo Hsi Kao, Yeh Wang, Ching Fa Yao

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The Michael addition reactions of β-nitrostyrenes 1 with 4-pentene-1- magnesium bromide 2a or 3-butene-1-magnesium bromide 2b generated nitronates 3 or 4. Medium to high yields of isoxazolidine derivatives 9 and 10 were obtained when nitronates 3 or 4 were treated with ethyl chloroformate and catalytic amount of 4-dimethylaminopyridine (DMAP) at room temperature in one-pot and the ratios of trans-9:cis-9 were from 1:3.00 to 1:4.06 and the ratios of trans-10:cis-1 0 were >99:1. The formation of compounds 9 is proposed to proceed through intramolecular nitrile oxide-olefin cycloadditions (INOC) because compounds 14a-d, obtained from the trapping of the nitrile oxides by ethyl chloroformate, could be isolated. The mechanism of the generation of compounds 10 is proposed to proceed through intramolecular alkoxycarbonyl nitronate-olefin cycloadditions (IAOC) to form intermediates N-(ethoxycarbonyl)isoxazolidines 13 and then eliminate EtOH and CO2 (or EtOCO2H) to yield the final products.

Original languageEnglish
Pages (from-to)7115-7128
Number of pages14
JournalTetrahedron
Volume55
Issue number23
DOIs
Publication statusPublished - 1999 Jun 4

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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