Regioselective synthesis of (Z)‐5‐methylene‐containing morpholin‐2‐ones

Abstract

AbstractAn 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.