N-Heterocyclic Carbene Ligand-Enabled C(sp(3))-H Arylation of Piperidine and Tetrahydropyran Derivatives

摘要

Pd-II-catalyzed C(sp(3))-H arylation of saturated heterocycles with a wide range of aryl iodides is enabled by an N-heterocyclic carbene (NHC) ligand. A C(sp(3))-H insertion step by the Pd-II/NHC complex in the absence of ArI is demonstrated experimentally for the first time. Experimental data suggests that the previously established NHC-mediated Pd-0/Pd-II catalytic manifold does not operate in this reaction. This transformation provides a new approach for diversifying pharmaceutically relevant piperidine and tetrahydropyran ring systems.