The Chemistry of 5-Oxodihydroisoxazoles. XII. Trapping of Derived Ketenimines with Lithium Amides and Alkyllithiums

Article abstract of DOI:10.1071/CH9950055

Isoxazolones unsubstituted at C 3 react with lithium amides or alkyllithiums to give ketenimines.The presence of an ethoxycarbonyl group at C 4 allows capture of this species by addition of a second equivalent of the lithiated species to give enolates which can be alkylated in situ.The presence of a phenyl group at C 4 gives a ketenimine which reacts intramolecularly in the presence of lithium amides, whereas alkyllithiums undergo addition in synthetically useful processes.