Synthesis of Chiral Bowl-Shaped N-Heterocycles via Pd-Catalyzed Enantioselective Intramolecular C-H Arylation

Chirality arising from curved molecular frameworks represents a unique stereochemical motif with growing importance in materials science and supramolecular chemistry, yet its catalytic asymmetric construction remains highly challenging. Herein, we report a palladium-catalyzed enantioselective intramolecular C-H arylation strategy for the synthesis of bowl-shaped tribenzo[b,d,f]azepines possessing framework-defined chirality. Enabled by a P-chiral monophosphine ligand, this transformation proceeds with high efficiency, delivering a diverse array of bowl-shaped N-heterocycles in excellent yields and enantioselectivities (up to 95% yield, 97% ee). The method accommodates a broad range of substrates and provides direct access to previously inaccessible bowl-shaped chiral frameworks. Mechanistic studies suggest that C-H activation is turnover-limiting and that stereocontrol originates from a monoligated palladium species. DFT studies were performed to elucidate the detailed reaction mechanism and the origins of enantioselectivity. This work establishes a general catalytic platform for constructing bowl-shaped chiral medium-sized rings and expands the synthetic toolbox for chiral π-functional molecules.