Unified, catalyst-controlled, bioinspired total synthesis of dimeric piperine alkaloids in batch and flow

We report a unified, bioinspired synthesis of nigramide R, chabamide, and dipiperamides F and G via catalyst-controlled photocatalytic dimerization of piperine. Selective [2+2] and [4+2] cycloadditions in batch or flow provide access to diverse dimeric alkaloids from a common precursor. A low-cost, 3D-printed continuous-flow PhotoFlow reactor improves efficiency and reproducibility, establishing a modular strategy for these compounds.