Synthesis of Diazatricyclic Molecules via Intramolecular Cycloaddition of Azomethine Ylides

Diazatricyclic molecules were synthesized via a modular approach. Starting from allylglycinol and amino acids, 2-ketopiperazines bearing an alkene unit were prepared. Upon heating with aldehydes, these 2-ketopiperazines generated azomethine ylides, which underwent intramolecular cycloaddition to construct the tricyclic core. The synthesis was completed in five or eight steps, with three or four substituents introduced in a modular fashion, respectively.