ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Photochemistry of heterocycles. 14.* Heteroatom and substituent effect on the photochemistry of condensed isoxazolines

Ľ. Fišera, Ľ. Štibrányi, A. Máťušová, and J. Oravkin

Department of Organic Chemistry, Slovak Technical University, CS-812 37 Bratislava

Abstract:   Photochemistry of isoxazolines, fused with 2,3-dihydrofuran, 2,3-dihydropyran, 2,3- and 2,5-dihydrothiophene as well as l,3-dithiep-5-ene has been described. Sulfur stabilized by N—О bond cleavage formed primary biradical better than oxygen; heteroatoms in ß-position relative to isoxazoline oxygen were more effective stabilizers than those in a-position. Primary photoproducts of sulfur-containing species as well as those having oxygen in a-position were photolabile. Biphenyl-substituted condensed isoxazolines were photostable (Ф < 0.001) . Irradiation of 3-phenyl-3a,4,6,6a-tetrahydro- furo[3,4-d]isoxazole in the presence of Fe(CO)₅ s produced 3-benzoyl-4-hydroxy- and 4-methoxytetrahydrofuran. Cycloadducts were prepared by 1,3-dipolar cycloaddition of nitrile oxide to the corresponding heterocycles.

Full paper in Portable Document Format: 405a693.pdf

Chemical Papers 40 (5) 693–705 (1986)