Photochemical Preparation of Pyrimidin-2(1H)-ones by Rhenium(I) Complexes with Visible Light

With visible light irradiation (lambda > 400 nm) of rhenium(I) complexes (P1-P4), a photochemical conversion from 3,4-dihydropyrimidin-2(1H)-ones to pyrimidin-2(1H)-ones at room temperature has been achieved with good to excellent yields in CH3CN-H2O solution containing CCl4 and K2CO3. Luminescence quenching study and product analysis reveal that photoinduced electron transfer between rhenium(I) complex P and 3,4-dihydropyrimidin-2(1H)-ones plays an important role in the initial event.