Tandem [3 + 2] Cycloaddition Reaction: Access to Polycyclic Quinolinone-Fused Pyrrolo[2,1-a]isoquinoline Scaffolds

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Green Chemistry

Background:

• Pyrrolo[2,1-a]isoquinoline scaffolds are prevalent in natural products and pharmaceuticals.
• Efficient and sustainable synthetic routes to these complex heterocycles are highly sought after.

Purpose of the Study:

• To develop a novel, catalyst-free domino protocol for the synthesis of functionalized quinolinone-fused pyrrolo[2,1-a]isoquinoline derivatives.
• To establish a green and efficient method with broad substrate scope and functional group tolerance.

Main Methods:

• A domino protocol involving cascade intermolecular aldehyde-amine condensation followed by intramolecular [3 + 2] cycloaddition.
• Utilized formyl-phenylpropiolamides and tetrahydroisoquinolines as starting materials.
• Conducted reactions under benign conditions without catalysts or additives.

Main Results:

• Successfully synthesized diverse functionalized quinolinone-fused pyrrolo[2,1-a]isoquinoline derivatives.
• Achieved good to high yields for the target compounds.
• Demonstrated broad functional group compatibility and substrate scope.

Conclusions:

• The developed domino protocol offers a concise, efficient, and green approach for synthesizing complex heterocyclic compounds.
• This method avoids the need for catalysts and additives, aligning with green chemistry principles.
• The strategy is suitable for preparing a wide array of valuable derivatives.