Hydroaminoalkyl Functionalization of Pyrimidin‐2(1H)‐ones by Visible Light Organophotocatalysis: A Radical Approach to Biginelli‐Type Dihydropyrimidines

Abstract Herein, we report a visible‐light‐mediated hydroaminoalkylation of pyrimidin‐2(1 H )‐ones via the aza‐Giese‐type reaction in presence of acridinium dye as photocatalyst under mild aerobic conditions. Using N ‐Boc protected aminoalkyl trifluoroborates as radical precursors and various pyrimidine‐2(1 H )‐one substrates, a diverse set of Biginelli‐type 3,4‐dihydropyrimidin‐2(1 H )‐ones was prepared in 31–73% yields. Further transformation of the products obtained enabled the synthesis of 3,6,7,7a‐tetrahydro‐1 H ‐pyrrolo[3,4‐d]pyrimidine‐2,5‐dione derivatives which showed promise as inhibitors of poly (ADP‐ribose) polymerase (PARP) enzymes (IC50 0.46–1.12 μM for PARP‐2 in a fluorometric assay).