Site-Selective C(sp³)-H and Switchable C(sp³)-H/C(sp²)-H Functionalization Enabled by Electron-Deficient Cp[*CF3]Ir(III) Catalyst and Photosensitizer

A site-selective functionalization of a C(sp³)-H bond was achieved in the presence of an intrinsically more reactive C(sp²)-H bond by controlling the orientation of a directing group via a photo-induced E/Z isomerization of an oxime ether. By combining E/Z isomerization and an electron deficient Cp[*CF3]Ir(III) catalyst, the scope of oxime ethers in C(sp³)-H functionalization was successfully expanded. Based on this strategy, the order of C-H activation was switchable and successive C(sp³)-H/C(sp²)-H and C(sp²)-H/C(sp³)-H double functionalizations were accomplished to construct densely functionalized structures.