Photocatalytic α-Tertiary Amine Synthesis via C-H Alkylation of Unmasked Primary Amines

A practical, catalytic entry to alpha,alpha,alpha-trisubstituted (alpha-tertiary) primary amines by C-H functionalisation has long been recognised as a critical gap in the synthetic toolbox. We report a simple and scalable solution to this problem that does not require any in situ protection of the amino group and proceeds with 100 % atom-economy. Our strategy, which uses an organic photocatalyst in combination with azide ion as a hydrogen atom transfer (HAT) catalyst, provides a direct synthesis of alpha-tertiary amines, or their corresponding gamma-lactams. We anticipate that this methodology will inspire new retrosynthetic disconnections for substituted amine derivatives in organic synthesis, and particularly for challenging alpha-tertiary primary amines.