Metal- and chlorine-free cross-dehydrogenative coupling of azaarenes with alkanes without sacrificial oxidants.

Minisci-like cross-dehydrogenative coupling of azaarenes with unactivated alkanes offers an appealing approach to bioactive alkyl-substituted heterocycles from abundant feedstocks. Traditionally, this net oxidative C-C bond formation process uses sacrificial chemical oxidants with the consequent waste generation. Here we report a chemical oxidant-free solution for this transformation, promoted by visible light at room temperature in the absence of metals and chlorinated solvents. The reaction relies on the interplay of a readily available 9-arylacridine and inexpensive pyridine N-oxide as pre-catalysts. A wide range of azaarenes and C(sp3)-H partners are compatible with this protocol, which was applied to the late-stage functionalization of bioactive molecules and the gram-scale synthesis of one API intermediate using flow technology. Preliminary mechanistic studies support the dual catalytic cycle with H2 evolution.