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, chlorinated solvents, or chlorine sources. The reaction is run under conventional photochemical conditions and does not require deoxygenation or anhydrous solvents. Remarkably, a readily available 9-arylacridine and the inexpensive pyridine N-oxide are used as catalyst precursors. A wide range of azaarenes and C-H partners are compatible with this protocol, which was applied to the late-stage functionalization of bioactive molecules. In addition, the gram scale synthesis of one API intermediate was accomplished using flow technology. Preliminary mechanistic studies were conducted to support the dual catalytic cycle.