Synthesis of 2,3-dihydroisoxazoles from propargylic N-hydroxylamines via Zn(II)-catalyzed ring-closure reaction
A novel cyclization reaction of propargylic N-hydroxylamines to 2,3, 5-trisubstituted 2,3-dihydroisoxazoles in the presence of catalytic amounts (10 mol %) of ZnI(2) and DMAP is reported. The methodology provides a mild new approach to this useful class of substituted heterocycles that complements extant methods. The unique reactivity of the propargylic N-hydroxylamine substrates in the presence of Zn(II) and DMAP may have additional applications in other, related alkyne cyclization reactions.
Laboratorium fur Organische Chemie, ETH-Zentrum, Universitatrasse 16, CH-8092 Zurich, Switzerland.
P
Aschwanden
DE
Frantz
EM
Carreira