Synthetic chemistry study reveals a cascade reaction forming stable isoquinolinium 1,4-zwitterions, enabling efficient, catalyst-free synthesis of bioactive pyrrolo[2,1-a]isoquinolines.
Key Points
To establish a scalable synthetic pathway toward oxygen-based isoquinolinium 1,4-zwitterions and apply them in constructing biologically relevant pyrrolo[2,1-a]isoquinolines.
Developed a 1,3-dipolar [3 + 2] cycloaddition and rearrangement cascade reaction using α-alkynyl trifluoromethyl sulfoxides and isoquinoline N-oxides.
Conducted catalyst-free [3 + 2] cycloaddition/elimination cascade reactions between the generated 1,4-zwitterions and conjugated ynones.
Synthesized oxygen-based isoquinolinium 1,4-zwitterions bearing a trifluoromethylsulfinyl group with high bench stability and reaction scalability.
Demonstrated efficient conversion of the zwitterionic intermediates into biologically relevant pyrrolo[2,1-a]isoquinoline scaffolds without requiring catalysts.