HIGHLY C3-SELECTIVE DIRECT ALKYLATION AND ARYLATION OF 2-PYRIDONES UNDER VISIBLE-LIGHT-PROMOTED PHOTOREDOX CATALYSIS

An Ir photoredox catalyst-mediated highly site-selective direct alkylation and arylation of 2-pyridones has been developed. Under visible-light-promoted conditions, ethyl 2-bromo-2,2-difluoroacetate couples with various 2-pyridones exclusively at the C3 position. A similar photoredox catalysis is also effective for the direct C3-arylation with diaryliodonium triflates. Thus, these reactions occurs under very mild conditions (blue LEDs irradiation and ambient temperature) to form the corresponding C3-alkylated and arylated 2-pyridones of potential interest in medicinal and pharmaceutical chemistry.