Asymmetric Syntheses Using Heteroarenesulfonyl Groups as a Highly Functional Protecting-activating Group

Enantioselective bond formation reaction is of great interest to medicinal or material science. In order to develop the synthetic methodology for these compounds, we designed heteroarenesulfonyl groups as an activating group for imines and a protecting group for amines. The heteroarenesulfonyl group was shown to be an efficient protective group, which has notable properties of high chiral inducibility and activation of the imino group toward the addition of several nucleophiles. Furthermore, we designed N-(heteroarenesulfonyl)prolinamides as novel organocatalysts. Enantioselective aldol reaction of acetone or acetaldehyde with various isatin derivatives using N-(2-thiophenesulfonyl)prolinamide afforded convolutamydine derivatives with high enantioselectivity.