Stereoselective Mannich Reaction of S‐Phenyl Thioesters Catalyzed by Bifunctional Organocatalysts

A highly stereoselective Mannich reaction of S‐phenyl thioesters was achieved by using bifunctional thiourea catalysts. Using a quinine‐derived C6′‐urea catalyst, the direct Mannich products of N‐tosyl imines and S‐phenyl thioesters were obtained in high yields and excellent diastereo‐ and enantioselectivities. magnified image