A new approach for the synthesis of spiro and gem-dimethyl-substituted 1,4-oxazepines from N-propargylic beta-enaminones


KARADENİZ E. , KELGÖKMEN Y. , ZORA M.

JOURNAL OF HETEROCYCLIC CHEMISTRY, vol.58, no.2, pp.466-477, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 58 Issue: 2
  • Publication Date: 2021
  • Doi Number: 10.1002/jhet.4183
  • Title of Journal : JOURNAL OF HETEROCYCLIC CHEMISTRY
  • Page Numbers: pp.466-477

Abstract

An efficient and general method for the synthesis of spiro-1,4-oxazepines and 3,3-dimethyl-1,4-oxazepines is reported. When treated with ZnI2 and AgSbF6 in refluxing DCE, cyclohexane-embedded N-propargylic beta-enaminones underwent 7-exo-dig cyclization to afford spiro-1,4-oxazepines, specifically 12-methylene-11-oxa-7-azaspiro[5.6]dodeca-7,9-dienes, in good to high yields. Accordingly, N-(1,1-dimethyl)propargylic beta-enaminones produced 3,3-dimethyl-1,4-oxazepines. Cyclization was found to be general for a diverse range of N-propargylic beta-enaminones with high efficiency and broad functional group tolerance. This operationally easy method might provide quick access to a library of functionalized spiro and gem-dimethyl-substituted 1,4-oxazepine derivatives of pharmacological interest.