Copper-Catalyzed Aerobic Aminooxygenation of Cinnamyl N-Alkoxycarbamates via Substrate-Promoted Catalyst Activation

We report a method for a ligand-enabled, copper-catalyzed aerobic aminooxygenation of internal alkenes. The synergistic combination of a phenanthroline-based ligand and substrate coordination promotes reduction of Cu(II) to Cu(I), resulting in a cyclization that proceeds via an amidyl radical pathway rather than a previously established aminocupration pathway. The complementary reactivity enabled by this switch in reaction mechanism provides access to different substrate classes and a considerably broadened scope for this transformation. Experimental evidence supports a free radical mechanism involving substrate-promoted reduction to Cu(I) as well as the role of O2 as both oxidant and functionalizing agent.