Unexpected Facile Sequential Halolactamization−Hydroxylation of 2,3-Allenamides with CuX<sub>2</sub> for the Efficient Synthesis of 4-Halo-5-hydroxypyrrol-2(5<i>H</i>)-ones<sup>†</sup>

2000-10-31T00:00:00Z (GMT) by Shengming Ma Hexin Xie
4-Halo-5-hydroxypyrrol-2(5<i>H</i>)-ones were synthesized from the efficient sequential halolactamization−hydroxylation reaction of 4-monosubstituted 2,3-allenamides with CuX<sub>2</sub> (X = Br, Cl) in high yields. Halolactamization of fully substituted 2,3-dienamide (<b>1f</b>) afforded 4-halo-pyrrol-2(5<i>H</i>)-ones.