Synthesis of substituted fused pyridines, pyrazines and pyrimidines by sequential Ugi/inverse electron demand Diels–Alder transformations

The synthesis of all four regioisomers of fused pyrrolidino-pyridines in a one-pot two-step sequential Ugi-inverse electron demand Diels–Alder reaction is described. Fused pyrrolidino-pyrazines, pyrrolidino-pyrimidines and azepinone pyridines can also be obtained in consecutive synthetic sequences.