Ultrasound‐Assisted In‐Water [3 + 2] Cycloaddition for the Synthesis of Fused Pyrrolizidine and Indolizidine Scaffolds with Anticancer Activity

An ultrasound‐assisted in‐water intramolecular (3 + 2) cycloaddition reaction is reported for the synthesis of fused‐pyrrolizidine and indolizidine frameworks. This approach eliminates the need for organic solvents, harsh reagents, and high temperatures. The method's practicality is demonstrated by gram‐scale synthesis, and the anticancer properties of the resulting compounds against the triple‐negative breast cancer cell line are demonstrated.