Isolation of Azomethine Ylides and Their Complexes: Iridium(III)‐Mediated Cyclization of Nitrone Substrates Containing Alkynes

Cat. at rest: [{IrCp*Cl2}2] readily catalyzes the redox cyclization of nitron alkynes (e.g., 1) to give azomethine ylides that can then react with electrophiles and π bonds. The unusual O‐bound azomethine complex 2was isolated and identified as the resting state of the catalyst in the azomethine ylide formation. Cp*=C5Me5.