α-Tertiary Primary Amine Synthesis via Photocatalytic C(sp3)-H Aminoalkylation.

Abstract

Facile access to sterically hindered α-tertiary primary amines via photocatalytic radical coupling of native C(sp3)-H substrates with N-unsubstituted ketimines is reported. LiBr was used as a hydrogen atom transfer reagent to cleave C(sp3)-H bonds to get alkyl radicals. The in situ-generated HBr can then serve as a Bronsted acid to activate N-unsubstituted ketimines readily for single-electron reduction to deliver α-amino radicals. As a consequence, radical-radical coupling affords primary amines with a congested α-tertiary substituent. This reaction is highlighted by simple and mild conditions, 100% atom-economy, and broad hydrocarbon substrate scope for benzyl ethers, cyclic ethers, benzyl alcohols, alkylarenes, and carbocycles.