The Chemistry of 5-Oxodihydroisoxazoles. X. Butyllithium and Lithium Diisopropylamide Promoted Rearrangements of 3-Unsubstituted Isoxazol-5(2H)-ones

Abstract

The reaction pathway of 3-unsubstituted isoxazol-5(2H)-ones with bases, proposed by Woodman^1-3 to proceed via four intermediates to azetidine-2,4-diones, has been confirmed by the isolation of products unequivocally derived from each of the intermediates. Isoxazol-5(2H)-ones substituted on nitrogen by methyl, phenyl, quinolin-2-yl and vinyl groups have been studied. The azetidine-2,4-diones have only been isolated when the intermediate enolate has been alkylated , but only reactive alkyl halides lead to useful syntheses.