C–H Amination Enabled [2+1+1+1] Annulation Reaction in Water: Access to Benzoxazoles

A novel and efficient four‐component reaction in water is reported, enabling the efficient synthesis of benzoxazoles from aldehydes, benzo‐1,2‐quinones, hydroxylamine hydrochloride, and water via a C−H amination strategy. Importantly, water is not only employed as the solvent but also used as the oxygen source of the benzoxazole skeletons, while inorganic hydroxylamine hydrochloride serves as the nitrogen source. Preliminary mechanistic studies...