Electrophilic Activation of Lactams with Tf2O and Pyridine: Expedient Synthesis of (±)-Tetraponerine T4

The electrophilic activation of lactams with triflic anhydride in the presence of pyridine was investigated by NMR. It was found that 2-pyrrolidone
led to the clean formation of the corresponding pyridinium imidate in 89% isolated yield. The subsequent nucleophilic addition of organometallic
reagents led to 2-substituted dihydropyridines. A synthesis of (±)-tetraponerine T4 with three simple building blocks was accomplished in 3
steps (38% yield).

本研究通过核磁共振波谱技术，探讨了三氟乙酰酐在吡啶存在下对内酰胺的亲电活化反应。研究发现，2-吡咯烷酮能够实现相应吡啶鎓亚胺的高效合成，其纯度达到89%。随后的亲核加成反应引入了有机金属试剂，得到2-取代二氢吡啶。利用三个简单的构建模块，成功在三个步骤中合成了（±）-四丙酮基衍生物T4，产率为38%。