Aromatic-Amide-Derived Nonbiaryl Atropisomer as Highly Efficient Ligand for Asymmetric Silver-Catalyzed [3 + 2] Cycloaddition

In this work, we have successfully determined that the aromatic amide-derived nonbiaryl atropisomer/silver complex (silver-Xing-Phos) is an effective catalyst system for the solvent-dependent exo-selective cycloaddition of glycine aldimino esters with chalcones or less-reactive methyl cinnamates to give the corresponding chalcone- or cinnamate-derived pyrrolidines with multiple stereogenic centers in good yields and high diastereoselectivities as well as excellent enantioselectivities. Remarkably, it is the first example of highly enantioselective silver-catalyzed [3 + 2] cycloaddition of methyl cinnamates with glycine aldimino esters.