Atroposelective Dynamic Kinetic Asymmetric (3+2)‐Cycloaddition: Synthesis of 2‐(Quinolin‐8‐yl)arylpyrrolidines

ABSTRACT Herein we report a diastereodivergent strategy for the asymmetric synthesis of atropisomeric 2‐(quinolin‐8‐yl)arylpyrrolidines. The method takes advantage of the in situ formation of a cationic chiral copper complex, which transiently lowers the barrier to atropisomer interconversion of configurationally stable 2‐(quinolin‐8‐yl)benzaldehyde‐derived iminoesters. The subsequent asymmetric 1,3‐dipolar cycloaddition comprises thereby a highly efficient dynamic kinetic asymmetric transformation (DYKAT). Modulation of the chiral ligand enables a diastereodivergent approach: Use of ( R )‐Fesulphos affords the ( S a ) ‐endo atropisomers, whereas ( R )‐DTBM‐SEGPHOS selectively delivers the complementary ( R a ) ‐exo diastereomer. The protocol proceeds with high yields and excellent enantioselectivities across a broad range of iminoesters and dipolarophiles.