The synthesis of 13-membered polyamine alkaloid, (S)-dihydroperiphylline, was achieved by the condensation of a chiral β-lactam, (S)-4-phenyl-2-azetidinone, with a cyclic imino ether of a 9-membered lactam, followed by reductive ring expansion. Both of these reactions proceeded with retention of configuration around the chiral center to give the optical pure 13-membered alkaloids.
                                    通过手性 β-内酰胺 (S)-
4-苯基-2-氮杂环丁酮与 9 元内酰胺的环状
亚胺醚缩合,合成了 13 元
多胺生物碱 (S)-二氢茶碱,然后是还原环扩展。这两个反应都在手性中心周围保留构型的情况下进行,得到光学纯的 13 元
生物碱。