Cycloadditions of N-Sulfonyl Nitrones Generated by Lewis Acid Catalyzed Rearrangement of Oxaziridines

摘要

The weak N-O bond of 1,2-isoxazolidines can undergo facile reductive cleavage to furnish 1,3-aminoalcohols. Due to the ease with which isoxazolidines can be processed into these synthetically valuable structures, considerable effort has been invested toward the development of methods for [3 + 2] nitrone cycloadditions. This enormous body of work, however, has focused primarily upon N-alkyl nitrones that produce 1,2-isoxazolidines whose N-substit-uents cannot be removed without concomitant cleavage of the sensitive N-O bond; cycloadditions of nitrones bearing easily hydrolyzed electron-withdrawing N-substituents are almost completely unexplored. Recently, 1,2-isoxazolidines have begun to attract significant attention as nucleoside analogues and synthetic transcriptase activators.