Cooperative Polar/Steric Strategy in Achieving Site-Selective Photocatalyzed C(sp3)-H Functionalization

Synergistic control over the SH2 transition states of hydrogen abstraction exploiting polar and steric effects provides a promising cooperative strategy for site‐selective C(sp3)−H functionalization using decatungstate anion photocatalysis. By using this photocatalytic approach, the C−H bonds of substituted lactones and cyclic ketones were functionalized selectively. In the remarkable case of 2‐isoamyl 4‐tert‐butyl cyclohexanone (1 t) bearing five methyl, five methylene, and three methine C−H bonds, one methine C−H bond in the isoamyl tether was selectively functionalized.