Iodine Promoted One-Pot Synthesis of 2-Aryl Benzoxazoles from Amidoximes via Oxidative Cyclization and Ring Contraction

A molecular I-2-promoted one-pot synthesis of 2-aryl benzoxazoles has been developed by using amidoximes rather than the limited 2-aminophenols or 2-haloamides as substrates. The amidoxime substrates provided unique and efficient strategies for converting readily available aniline and benzaldehyde precursors into valuable chemicals. This transformation proceeded smoothly under transition-metal-free conditions through a sequential oxidative cyclization and ring contraction, and provided a potential route for introducing certain groups at any site of the scaffold.