Diverse Isoquinoline Scaffolds by Ugi/Pomeranz–Fritsch and Ugi/Schlittler–Müller Reactions

[Image: see text] The Pomeranz–Fritsch reaction and its Schlittler–Müller modification were successfully applied in the Ugi postcyclization strategy by using orthogonally protected aminoacetaldehyde diethyl acetal and complementary electron rich building blocks. Several scaffolds, including isoquinolines, carboline, alkaloid-like tetrazole-fused tetracyclic compounds, and benzo[d]azepinone scaffolds, were synthesized in generally moderate to good yield. All our syntheses provide a short MCR-based sequence to novel or otherwise difficult to access scaffolds. Hence, we foresee multiple applications of these synthesis technologies.