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

1,3-Dipolar Cycloadditions of Heterocycles. 27. Stereoselective Preparation of 3-Aryl-4-oxo-6-alkoxy-3a,4,6,6a-tetrahydrofuro[3,4-d]isoxazoles and 2-Phenyl-6-aryl-3-hydroxy-1,2,3,3a,6a,7-hexahydroisoxazolo[4,5-d]pyridazin-7-ones

P. Oravec, Ľ. Fišera, N. Prónayová, and R. Gažo

department of Organic Chemistry, Faculty of Chemical Technology, Slovak Technical University, CS-812 37 Bratislava

Abstract: The synthesis of 3-aryl-4-oxo-6-alkoxy-3a,4,6,6a-tetrahydrofuro[3,4-d]isoxazoles III-XV was carried out straightforwardly and highlighted by a regio- and stereoselective 1,3-dipolar cycloaddition of substituted benzonitrile oxides with 5-methoxy- or 5-ethoxy-5H-furan-2-one. In each case a cycloadduct results from an anti approach to the 5-alkoxy substituent, the oxygen of the 1,3-dipole being attached to C-4 of furan. Reaction of III-XV with phenylhydrazine led exclusively to exo-hexahydroisoxazolo[4,5-d]pyridazin-7-ones with trans relationship of the H-3 to the H-3a and H-6a bridge hydrogen atoms.

Full paper in Portable Document Format: 462a104.pdf

Chemical Papers 46 (2) 104–108 (1992)