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

Synergistic control over the SH 2 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.