Copper-mediated domino C-H iodination and nitration of indoles.

An efficient and cost-effective copper-mediated aerobic oxidative C-H iodination and nitration of indoles via double C-H functionalization is reported. The domino process proceeds smoothly under mild aerobic conditions to give 3-iodo-2-nitroindoles in one step with high regioselectivity and a broad substrate scope. The mechanism of the iodination step is proposed to proceed via a Cu(iii)-iodide species that undergoes electrophilic addition at the C3 position of the indole motif. The subsequent nitration step involves a sequence of C-H activation, nitro radical oxidative addition, and reductive elimination.