Expeditious Synthesis of Chiral Imidazolidines and 1,2-Diamines via Photocatalytic [3 + 2] Cycloaddition of Chiral Sulfinamides with Azomethine Ylides

This study introduces the first example of a photocatalytic [3 + 2] cycloaddition reaction to efficiently generate novel chiral imidazolidines using a chiral sulfinamide. A broad range of substrates, including different (S)-N-tert-butanesulfinyl imines and dipole precursors, were found to be compatible, delivering chiral imidazolidines in good yields with high diastereoselectivity (up to 93% yield, up to >25:1 dr). The reaction mechanism was investigated through radical trapping experiments. Furthermore, chiral 1,2-diamines were efficiently obtained with excellent enantioselectivities (up to 100:0 er).