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, cilt.58, sa.2, ss.466-477, 2021 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 58 Konu: 2
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1002/jhet.4183
  • Dergi Adı: JOURNAL OF HETEROCYCLIC CHEMISTRY
  • Sayfa Sayıları: ss.466-477

Özet

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.