Hexafluoro-2-propanol Promotes para-Selective C-H Amination of Free Anilines with Azodicarboxylates

An effective, mild, and clean method for the C-H amination of free anilines with azodicarboxylates in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) without the need for any additional catalysts or reagents was developed. The reaction was found to be highly regioselective and provided a series of p-aminophenylhydrazine derivatives in excellent yields. Moreover, compatibility with a free amino group makes this protocol an attractive strategy in synthetic chemistry.