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.