Minimization of Back-Electron Transfer Enables the Elusive sp3 C-H Functionalization of Secondary Anilines.

Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C-H functionalization.