Palladium(II)-Catalyzed C(sp)-C(sp2) Coupling: A Direct Approach to Multi-Substituted Pyrrolo[1,2-a]pyrazines

A direct synthesis of multi-substituted pyrrolo[1,2-a]pyrazines via palladium(II)-catalyzed C(sp)-C(sp(2)) cascade coupling and intramolecular cyclization in the presence of ligand was developed. This reaction originates from phenylboronic acids and readily synthesized 2-carbonyl- or 2-formylpyrroloacetonitriles, and affords products in good to excellent yields for a diversity of substrates. Additionally, a possible mechanism for the transformation is proposed.

Automated summary

This study presents a direct synthesis of multi-substituted pyrrolo[1,2-a]pyrazines via palladium(II)-catalyzed C(sp)-C(sp(2)) cascade coupling and intramolecular cyclization. The reaction originates from phenylboronic acids and readily synthesized 2-carbonyl- or 2-formylpyrroloacetonitriles, providing products in good to excellent yields for a diversity of substrates. Furthermore, a possible mechanism for the transformation is proposed.