N-N Bond Formation Using an Iodonitrene as an Umpolung of Ammonia: Straightforward and Chemoselective Synthesis of Hydrazinium Salts

The formation of hydrazinium salts by N-N bond formation has typically involved the use of hazardous and difficult to handle reagents. Here, mild and operationally simple conditions for the synthesis of hydrazinium salts are reported. Electrophilic nitrogen transfer to the nitrogen atom of tertiary amines is achieved using iodosylbenzene as oxidant and ammonium carbamate as the N-source. The resulting process is highly chemoselective and tolerant to other functional groups. A wide scope is reported, including examples with bioactive molecules. Insights on the structure of hydrazinium salts were provided by X-ray analysis.