A novel approach to bis-isoxazolines using a latent form of cyclopentadienone

Article abstract of DOI:10.1039/b005520o

The synthesis of a range of both racemic and homochiral 4-alkyl- and 4-aryl-8-hydroxy-2-oxa-3-azabicyclo[3.3.0]oct-3-en-6-ones (isoxazolines) from the 1,3-dipolar cycloaddition reactions between alky- and aryl-nitrile oxides and 4-alkoxycyclopent-2-enomes was described. Elimination of the 8-hydroxy group and subsequent additional cycloaddition reactions provided 5,9-disubstituted-3,11-dioxa-4,10-diazatricyclo[6.3.0^1,8.0^{2 ,6}]undeca-4,9-dien-7-ones formally derived fromcyclopentadienone. The results showed that in the structures studied the nonhydrogen atoms were included in geometric positions and given thermal parameters equivalent to 1.2 times those of the atoms to which they were attached.