Skeletal editing of 4-arylpyrimidines into diverse nitrogen heteroaromatics via four-atom synthons

Scaffold hopping is a key strategy in drug discovery. While one-to-one scaffold hopping strategies are thriving and evolving, one-to-multiple strategies remain challenging to design. We present here a distinct scaffold hopping strategy for the skeletal editing of pyrimidines into a wide range of heteroarenes through the addition of nucleophiles, ring-opening, fragmentation, and ring-closing (ANROFRC) processes. This method features the in situ generation of a vinamidinium salt intermediate, which serves as a unique N-C-C-C four-atom (A4) synthon that reacts with A1 and A2 synthons. Mechanistic studies reveal that C4-aryl substituents play a crucial role in stabilizing the vinamidinium salt intermediate. This work provides a powerful tool for the systematic construction and modification of nitrogen heterocycles, thereby expanding conventional molecular editing techniques.