A tandem oximation-cyclization route to Δ2-isoxazolines

3,5-Disubstituted Delta(2)-isoxazolines can be prepared from the corresponding beta,gamma-unsaturated ketones by treatment with hydroxylamine hydrochloride and sodium hydroxide. Evidence indicates that the mechanism of this reaction involves the formation of three intermediates; oximation of the ketone, rearrangement of the alkene, and intramolecular Michael addition of the resulting alpha,beta-unsaturated oxime. (C) 2007 Elsevier Ltd. All rights reserved.