Under the photocatalyst (PC)/O2 catalytic system, visible light excites PC, producing the species PC*. This excited state facilitates the SET that converts intermediate B into C. The photocatalyst radical anion (PC˙-) is then oxidized back to its ground state by molecular oxygen (O2). Finally, deprotonation of intermediate D via hydrogen abstraction yields the desired product 29 (R 1 = H; R 2 = Ph).