Synthesis and photooxygenation of 3-(p-substituted phenyl)-3a,8a-dihydro-4H-cyclohepta[d]isoxazoles: Facial selectivity

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Olgun M. E., Menzek A., ŞAHİN E., ÇETİNKAYA Y.

Turkish Journal of Chemistry, cilt.48, sa.4, ss.691-700, 2024 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 48 Sayı: 4
  • Basım Tarihi: 2024
  • Doi Numarası: 10.55730/1300-0527.3688
  • Dergi Adı: Turkish Journal of Chemistry
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, TR DİZİN (ULAKBİM)
  • Sayfa Sayıları: ss.691-700
  • Anahtar Kelimeler: density functional theory, Diels–Alder reaction, facial selectivity, isoxazole, photooxygenation
  • Atatürk Üniversitesi Adresli: Evet

Özet

Two 3-(p-substituted phenyl)-3a,8a-dihydro-4H-cyclohepta[d]isoxazoles were synthesized by 1,3-dipolar cycloaddition of the corresponding nitrile oxides with cycloheptatriene. Two endoperoxides were synthesized as facially selective and single products in high yields (93%–95%) from the reactions of isoxazole derivatives with singlet oxygen. The exact configurations of the endoperoxide with a methyl group in the phenyl ring and the diol synthesized from it were confirmed by X-ray analysis. To elucidate the mechanism, the formation energy of the endoperoxide was investigated by simulations using the software package Gaussian 09 and density functional theory calculations via the M06-2X/6-311+G(d,p) level method in dichloromethane. The results were consistent with experimental findings showing the formation of isoxazole products.