A hypervalent iodine-mediated spirocyclization of 2-(4-hydroxybenzamido)acrylates – unexpected formation of δ-spirolactones
作者:Christian Hempel、Nicole M. Weckenmann、C. Maichle-Moessmer、Boris J. Nachtsheim
DOI:10.1039/c2ob26815a
日期:——
On the way towards a new total synthesis of (S)-arogenate, a novel aryl-λ3-iodane-mediated oxidative spirocyclization of para-substituted phenol derivatives has been discovered. Starting from easy accessible 2-(4-hydroxybenzamido)acrylates we could construct spirocyclic lactams in up to 52% yield. Under alternative reaction conditions the same precursors underwent an unexpected oxidative spirocyclization yielding a novel δ-spirolactone in up to 70% yield.
在(S)-芳香酸的新总合成过程中,发现了一种新型的芳基-λ3-碘酸盐介导的氧化螺环化反应,适用于对位取代的酚衍生物。我们从易于获取的2-(4-羟基苯酰氨基)丙烯酸酯出发,成功构建了高达52%产率的螺环内酰胺。在不同的反应条件下,同样的前体经历了意想不到的氧化螺环化反应,生成了一种新型的δ-螺内酯,产率高达70%。