Lewis Acid Catalyzed Dynamic Kinetic Asymmetric Transformation of Racemic N-Sulfonylaziridines.

The first Lewis acid catalyzed stereoconvergent transformation of racemic 2-(hetero)aryl- N-sulfonylaziridines via C-N bond cleavage with nucleophiles is presented. This includes the [3 + 2] annulations with (hetero)aromatic aldehydes and 1,3-disubstituted indoles, asymmetric Friedel-Crafts type reaction with electron-rich (hetero)arenes, and asymmetric aminolysis with amines, providing facile access to chiral 1,3-isoxazolidines, pyrroloindolines, 2-(hetero)arylphenethylamines, and vicinal diamines. This method features a simple and cheaply available complex of Cu(I)-chiral BINAP catalyst, excellent yield and high diastereo- and enantioselectivities, and mild reaction conditions. A mechanism involving type I dynamic kinetic asymmetric transformations (DyKATs) of the racemic aziridines is proposed based on the results of control experiments.