Taming Enolate Regioselectivity: Catalyst-Guided Divergent Synthesis of Atropisomeric Pyridones via Switchable C- and O-Acylation

Catalyst-guided divergent synthesis marks a paradigm shift in organic synthesis, offering transformative potential to access structurally diverse molecules. By leveraging symmetric enolates as programmable synthons, we established a catalyst-guided atroposelective C- and O-acylation for the switchable divergent synthesis of N-C and N-N axially chiral pyridones. The outstanding enantio- and regiocontrol (C- vs O-acylation) originated from the development of new chiral 4-pyrrolidinopyridine (PPY) derivatives and PPY-N-oxides as orthogonal acyl-transfer catalysts. These catalysts exhibited complementary reactivity and selectively delivered C- or O-acylated products. Notably, their exceptional atroposelective control capabilities enabled access to both C-N and N-N atropisomers, expanding the scope of accessible chiral architectures of conventional catalysts in this class. The synthetic applications were further displayed by the postfunctionalization, underscoring the methodology's potential in accessing structurally complex chiral frameworks.