N–N–N–N–O Benzotriazole Carbamates by Hypervalent Iodane Mediated Cross-Dehydrogenative N–N Coupling

While in high demand, synthetic methods for intermolecular dehydrogenative hetero N–N coupling reactions remain very rare, in spite of some seminal but limited developments these past few years. This is largely due to the broad diversity of more favorable side reactions that can occur upon the oxidation of organic amines, amides and related, such as competing C–C or C–N couplings, or even skeletal rearrangements. We report herein our latest research efforts in this field, focused on aromatic and aliphatic N -alkoxy carbamates and their dehydrogenative N–N coupling with benzotriazoles. This process is enabled by very simple and mild reaction conditions, affording the coupling products in high yields, even at a larger scale. The ability of the PIDA (diacetoxyiodobenzene) oxidant to produce the N–N bond is demonstrated by an unprecedented X-ray structure of the N–N–N–N–O scaffold. Mechanistic insights, including radical trapping and isotope competition experiments, as well as computational investigations, suggest a radical mechanism.