An efficient, one-pot, protecting-group-free, and regioselective protocol to obtain enantiomerically pure (Z)-5-methylene-containing morpholin-2-ones, using α-amino acids and 5-bromo-4-methoxy enones as selective starting materials, is reported. The reaction was fully selective in providing the (Z)-regioisomer in all cases, regardless of the α-amino acid used; however, when a secondary amino group was used, only the (E)-isomer was observed. The synthesized compounds were obtained at yields of up to 92%, and their structure was unambiguously assigned by x-ray and 2D-NMR experiments.

中文翻译：

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含(Z)-5-亚甲基的吗啉-2-酮的区域选择性合成

一种高效、一锅、无保护基和区域选择性方案，以 α-氨基酸和 5-溴-4-甲氧基烯酮为原料，获得对映体纯的 ( Z )-5-亚甲基含吗啉-2-酮据报道，选择性起始材料。无论使用何种 α-氨基酸，该反应在所有情况下都完全选择性地提供 ( Z )-区域异构体；然而，当使用仲氨基时，仅观察到( E )-异构体。合成的化合物收率高达92%，并且通过X射线和2D-NMR实验明确了其结构。