Halogen-Bond-Promoted α-C-H Amination of Ethers for the Synthesis of Hemiaminal Ethers

A simple halogen-bond-promoted alpha-C-H amination of ether/thioether with a variety of N-H compounds has been accomplished. In the presence of low-cost and readily available perfluorobutyl iodide, a diverse range of hemiaminal ether derivatives, including the valuable hydrazone hemiaminal ethers, were quickly assembled under thermal or visible-light irradiation conditions. Mechanistic studies suggest that a halogen-bond adduct was formed and a radical chain pathway might be operative. Synthetic application of the method has been demonstrated via the preparation of the anti-viral and anti-tumor drug, Tegafur.