Photoinduced Electron Donor Acceptor Complex‐Enabled α‐C(sp3)‐H Alkenylation of Amines

Allylic amines are prevalent and vital structural components present in many bioactive compounds and natural products. Additionally, they serve as valuable intermediates and building blocks, with wide‐ranging applications in organic synthesis. However, direct α‐C(sp³)−H alkenylation of feedstock amines, particularly for the preparation of α‐alkenylated cyclic amines, has posed a longstanding challenge. Herein, we present a general, mild, operationally simple, and transition‐metal‐free α‐alkenylation of various readily available amines with alkenylborate esters in excellent E/Z ‐ and diastereoselectivities. This method features good compatibility with water and oxygen, broad substrate scope, and excellent functional group tolerance, thereby enabling the late‐stage modification of various complex molecules. Mechanistic studies suggest that the formation of a photoactive electron donor‐acceptor complex between 2‐iodobenzamide and the tetraalkoxyborate anion, which subsequently undergoes photoinduced single electron transfer and intramolecular 1,5‐hydrogen atom transfer to generate the crucial α‐amino radicals, is the key to success of this chemistry.