Base-Controlled Dual Pd Catalysis Enabling Tunable Tandem C(sp3)-H Cyclopalladation-Annulation and 6-endo-trig Heck Cyclization.

Harnessing the divergent reactivity of multifunctional substrates under palladium catalysis offers a powerful route to molecular complexity. A base-controlled, switchable dual reactivity of a single Pd catalyst-ligand system toward a designed haloarene substrate has been established, enabling either tandem C(sp3)-H cyclopalladation-annulation or 6-endo-trig Heck cyclization. Precise base-solvent selection directs access to diverse naphthalene, dihydronaphthalene, and (hetero)polyarene scaffolds, including bioactive natural product cores and advanced materials.