Flash vacuum pyrolysis of oxo-stabilised phosphonium ylides containing methoxythiophene and methylthiophene groups

R. Alan Aitken, Alasdair N. Garnett

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Ten new oxo-stabilised phosphonium ylides containing substituted thiophene groups, as well as two deuterium-labelled analogues, are prepared and fully characterised. Upon flash vacuum pyrolysis at 800 °C, the simpler examples undergo extrusion of Ph3PO coupled with domino cyclisation to give thieno[3,2-b]furan and thieno[3,4-b]furan products but the corresponding approach to a thieno[2,3-b]furan fails. One ylide designed to give a thieno[3,4-b]furan instead gives phenylbutadiyne and 2-phenyl-3-vinylthiophene at 725 °C and the mechanism of this unusual process is elucidated by deuterium labelling. Attempts to access more complex heterocyclic products from extended methoxythienyl ylides failed. Two ylides bearing a 3-methyl-2-thienylacryloyl group gave 5-benzylbenzothiophene, 5-(α-methylbenzyl)benzothiophene and fluoreno[3,4-b]thiophene upon FVP at 800 °C and the mechanism was again elucidated by deuterium labelling.
Original languageEnglish
Pages (from-to)369-378
Number of pages10
JournalJournal of analytical and applied pyrolysis
Volume135
Early online date23 Aug 2018
DOIs
Publication statusPublished - 16 Oct 2018

Keywords

  • Flash vacuum pyrolysis
  • Phosphonium ylide
  • Thienofuran
  • Benzothiophene
  • Fluorenothiophene
  • Radical cyclisation

Fingerprint

Dive into the research topics of 'Flash vacuum pyrolysis of oxo-stabilised phosphonium ylides containing methoxythiophene and methylthiophene groups'. Together they form a unique fingerprint.

Cite this