Hydrative Aminoxylation of Ynamides: One Reaction, Two Mechanisms. Issue 10 (24th January 2018) - Pinto, Alexandre
Abstract: Organic synthesis boasts a wide array of reactions involving either radical species or ionic intermediates. The combination of radical and polar species, however, has not been explored to a comparable extent. Herein we present the hydrative aminoxylation of ynamides, a reaction which can proceed by either a polar‐radical crossover mechanism or through a rare cationic activation. Common to both processes is the versatility of the persistent radical TEMPO and its oxidised oxoammonium derivative TEMPO + . The unique mechanisms of these processes are elucidated experimentally and by in‐depth DFT‐calculations. Abstract : Same product, different mechanisms : Taking advantage of the versatility of TEMPO and its oxidised TEMPO + oxoammonium derivative, we report the TEMPO‐mediated hydrative aminoxylation of ynamides via the intermediacy of keteniminium ions, an unusual reaction that can proceed by either a polar‐radical crossover mechanism or a cationic hydrative pathway.