Molybdenum Hexacarbonyl Promoted Ring-Opening of Hydroxyimino Isoxazoles: Unexpected Pyrazole Formation

Abstract

Fused isoxazoles underwent reductive ring-opening in the presence of molybdenum hexacarbonyl to give the corresponding β-disubstituted compounds. 3,6,6-Trimethyl-6,7-dihydro-1,2-benzisoxazol-4(5H)-one oxime underwent reductive ring-opening in the presence of molybdenum hexacarbonyl to give 3,6,6-trimethyl-6,7-dihydro-1H-indazol-4(5H)-one. A mechanism is proposed.