Light-Induced Alkylation of (Hetero)aromatic Nitriles in a Transition-Metal-Free C–C-Bond Metathesis

Abstract

A light-induced C–C-σ-bond metathesis was achieved through transition-metal-free activation of an unstrained C(sp 3 )–C(sp 3 )-σ-bond in 1-benzyl-1,2,3,4-tetrahydroisoquinolines. A photoredox-mediated single-electron oxidation of these precursor amines yield radical cations which undergo a homolytic cleavage of a C(sp 3 )–C(sp 3 )-σ-bond rather than the well-known α-C–H-scission. The resulting carbon-centered radicals are used in the ipso -substitution of (hetero)aromatic nitriles proceeding through another single-electron transfer-mediated C–C-bond cleavage and formation.