Stereocontrolled Addition of π-type Nucleophiles to a Bicyclic N-Acyliminium Ion. New Access to <i>trans</i>-2,6-Disubstituted Piperidine Substructures
Bicyclic N-acyliminium ion I, generated in situ by treatment of aminoether 4 with Lewis acids, smoothly reacted with Ï-type nucleophiles, leading exclusively to the trans adducts.
生成的双环 N-酰亚胺阳离子 I 通过氨醚 4 与路易斯酸反应原位生成,能够顺利地与 π 型亲核试剂反应,且仅产生反式加成物。
Efficient Total Synthesis of Enantiopure (−)-Porantheridine