Visible-Light Photoredox-Catalyzed Iminyl Radical Formation by N-H Cleavage with Hydrogen Release and Its Application in Synthesis of Isoquinolines.

An unprecedented visible-light photoredox-catalyzed iminyl radical formation by N-H cleavage with H2 release has been developed. Its application in the synthesis of various isoquinolines and related polyaromatics in high atom economy at ambient temperature by applying a photosensitizer, Acr+-Mes ClO4-, and a new cobalt catalyst, Co(dmgH)2(4-CONMe2Py)Cl is reported. Mechanistic investigations indicated that the generated iminyl radical initiates the cascade C-N/C-C bonds formation and the catalytic cycle occurs by a simultaneous oxidative as well as reductive quenching pathway.