The synthesis of furo[3,4-d]isoxazoles (3) and inter- and intramolecular cycloaddition reactions (to 4, 5a,b) are reported. The structures of 3k, 5b and 6 have been clarified by X-ray crystallography. Quantum chemical calculations (AM1, PM3, ab initio, density functional methods) concerning the geometry and the different reactivity of benzo[c]furans and furo[3,4-d]isoxazoles were performed.
Reck, S., Bluhm, K., Debaerdemaeker, T., Declercq, J.-P., Klenke, B., & Friedrichsen, W. (1996). Intramolecular cycloadditions with isobenzofurans .12. Synthesis and reactions of furo[3,4-d]isoxazoles. Heterocycles, 43(6), 1165-1170. https://doi.org/10.3987/COM-96-7434 (Original work published 1996)