Reductive cleavage of fused isoxazoles with chlorotrimethylsilane/sodium iodide: A convenient route to 3,4-disubstituted isoxazoles

Abstract

The reaction of 7-aryl-4,5-dihydro-7H-pyrano- and 6-aryl-4H,6H-furo[3,4-c]isoxazoles with a combination of TMSCl/NaI afforded reductively ring cleaved 3,4-disubstituted isoxazoles (3, 4, 6 and 7). TMSCl/NaI (5/10 equivalents) mediated reductive cleavage of 3,6-disubstituted 4H,6H-furo[3,4-c]isoxazole (5) efficiently provided the key intermediates (6) and (7) leading to new fused isoxazoles, 4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridine (8,9) via further synthetic modification.