Chiral Phenanthroline Ligand-Promoted Iron-Catalyzed Enantioselective Intramolecular C(sp³)−H Amination

Chiral imidazolidin-2-ones are a kind of important N-heterocycles in bioactive molecules and can be converted to valuable chiral vicinal diamines. It is of great significance to develop catalytic asymmetric transformations for the synthesis of chiral N -heterocycles which play a significant role in drug development. Herein, an asymmetric intramolecular C(sp³)−H amination of N-benzoyloxyurea via 1,5-hydrogen atom transfer (HAT) is developed by using earth-abundant iron as the catalyst and chiral amino-acid derived phenanthroline as ligand, affording a series of chiral imidazolidinones in moderate-to-good yields (up to 68%) and enantiomeric ratios (up to 81:19). It is worth noting that this is one of the very few examples of iron-catalyzed enantioselective intramolecular C(sp³)−H aminations realized with a nonenzymatic catalyst.