Photoredox/Palladium Promoted Selective Dialkylation of α , α ′‐Amino C(sp ³ )H Bonds from N , N‐ Dimethyl‐1‐sulfonyl Enamines

Enamines serve as significant building blocks in α ‐(asymmetric) functionalization of aldehydes and key intermediates in the direct deoxygenation of amides to β ‐functionalized amines. However, examples on the selective alkylation of α ‐amino C(sp 3 )H bonds of enamines are rare, and especially, the dialkylation of α , α ′‐amino C(sp 3 )H bonds is still less explored. Herein, we report an acridinium–palladium‐catalyzed operationally simple method for the facile dialkylation of N , N‐ dimethyl‐1‐sulfonyl enamines, which is particularly efficient for the alkenyl retention cases, providing diverse electron‐deficient N , N‐ dialkyl‐1‐sulfonyl enamines with exceptional functional group tolerance and complete regiocontrol. Control experiments and detailed mechanism study reveal that the electron neutral photoredox catalysis proceeds through a step‐wise mechanism, and the radical palladium intermediate plays an important role in the second alkylation progress.