TEMPO-mediated aerobic oxidative synthesis of 2-aryl benzoxazoles via ring-opening of benzoxazoles with benzylamines

A simple and efficient TEMPO-mediated system for aerobic oxidative synthesis of 2-aryl benzoxazoles from readily available primary benzylic hetero amines is presented in one pot. The reaction proceeds through the ring-opening followed by condensation with benzylamines. These metal-free, straightforward reactions worked well a wide range substrates, yielding moderate to good yields under mild conditions using air as an external green oxidant.