A set of enantiomerically pure N-disubstituted β-amino alcohols was chlorinated by treatment with thionyl chloride. This reaction gave a mixture of regioisomeric chlorides that could be equilibrated to the more stable regioisomer by heating in DMF. The chlorides thus obtained were engaged in an intramolecular anionic ring-closure and gave access to fully protected enantio- and diastereomerically pure 2,3-cis-disubstituted azetidinic amino acids. One of the latter was deprotected and included in a short peptide sequence.
                                    一套对映体纯的N-二取代β-
氨基醇通过与
氯化亚
硫酰的处理进行了
氯化反应。该反应产生了一种区域异构体
氯化物的混合物,可以通过在
DMF中加热转化为更稳定的区域异构体。由此获得的
氯化物参与了一次分子内阴离子环闭合反应,得到了完全保护的对映体和二态异构体纯的2,3-顺式二取代氮杂环丁
胺类氨基酸。其中一种
氨基酸被脱保护,包含在一个短肽序列中。