Metal Free Simple and Efficient Synthesis of Tetrahydropyrrolo[1,2-a]- Pyrazine Based on a Cascade Strategy

A simple and efficient synthesis of pyrrolo[1,2-a]pyrazine using Schiff base formation, intramolecular cyclization (or N-alkylation), and Pictet–Spengler type reaction (hetero-aromatisation) has been developed. In this chemistry, metal-free, cost and time-effective processes have been highlighted to afford the complex nitrogenous scaffold using simple starting materials.