Thiol-Mediated α-Amino Radical Formation via Visible-Light-Activated Ion-Pair Charge-Transfer Complexes

Visible-light-activated electron donor-acceptor complexes offer distinct reaction pathways for the synthesis of complex molecules under mild conditions. Herein, we report a method for the reductive generation of a-amino radicals via the reaction of a visible-light-activated ion-pair charge-transfer complex formed between an in situ-generated alkyl-iminium ion and a thiophenolate. This distinct activation mode is demonstrated through the development of a multicomponent coupling reaction to form substituted aminomethyl-cyclopentanes from secondary amines, cyclopropyl aldehydes, and alkenes. The operationally straightforward transformation displays broad scope and provides a means to generate cyclic amine-containing scaffolds from readily available feedstocks.

Automated summary

Visible-light-activated electron donor-acceptor complexes provide unique reaction pathways for the synthesis of complex molecules under mild conditions. This study demonstrates a method for the reductive generation of α-amino radicals through the reaction of a visible-light-activated ion-pair charge-transfer complex, allowing for the development of a multicomponent coupling reaction to form substituted aminomethyl-cyclopentanes. The operationally straightforward transformation is versatile and enables the generation of cyclic amine-containing scaffolds from readily available feedstocks.