P. Aschwanden et al., Synthesis of 2,3-dihydroisoxazoles from propargylic N-hydroxylamines via Zn(II)-catalyzed ring-closure reaction, ORG LETT, 2(15), 2000, pp. 2331-2333
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A novel cyclization reaction of propargylic N-hydroxylamines to 2,3,5-trisu
bstituted 2,3-dihydroisoxazoles in the presence of catalytic amounts (10 mo
l %) of Znl(2) and DMAP is reported. The methodology provides a mild new ap
proach to this useful class of substituted heterocycles that complements ex
tant methods. The unique reactivity of the propargylic N-hydroxylamine subs
trates in the presence of Zn(II) and DMAP may have additional applications
in other, related alkyne cyclization reactions.