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. Thesynergistic combination of a phenanthroline-based ligand andsubstrate coordination promotes reduction of Cu(II) to Cu(I),resulting in a cyclization that proceeds via an amidyl radicalpathway rather than a previously established aminocuprationpathway. The complementary reactivity enabled by this switch inreaction mechanism provides access to different substrate classesand a considerably broadened scope for this transformation.Experimental evidence supports a free radical mechanism involvingsubstrate-promoted reduction to Cu(I) as well as the role of O2 asboth oxidant and functionalizing agent.

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