Photocatalytic [4 + 2] Annulation Reaction of Amine and Olefin Mediated by Benzophenone for Tetrahydroquinoline Synthesis

Herein, the intermolecular radical tandem reaction of tertiary aniline and olefin promoted by benzophenone, which acts as a photosensitizer to accelerate single‐electron transfer, hydrogen atom transfer, and α ‐aminoalkyl radical formation is reported. The reaction proceeds under mild conditions, exhibits a broad substrate tolerance and high diastereoselectivity, as well as confirms that hydrogen gas is produced in the reaction system, providing a convenient and efficient method for the synthesis of tetrahydroquinoline derivatives.