Construction of 1,3‐Nonadjacent Stereogenic Centers Through Enantioselective Addition of α‐Thioacetamides to α‐Substituted Vinyl Sulfones Catalyzed by Chiral Strong Brønsted Base
Azusa Kondoh, Rihaku Ojima, Sho Ishikawa, Masahiro Terada
Abstract
An enantioselective addition reaction for the construction of 1,3-nonadjacent stereogenic centers is developed by means of a chiral strong Brønsted base catalyst. The chiral sodium ureate catalyst efficiently promoted the reaction of α-thioacetamides as less acidic pronucleophiles with vinyl sulfones having a variety of α-substituents including aryl, alkyl and halo groups, and α-phenylacrylates, accomplishing the construction of various 1,3-nonadjacent stereogenic centers in highly diastereo- and enantioselective manners. This is a rare example of the construction of 1,3-nonadjacent stereogenic centers with less acidic pronucleophiles. In addition, the application of Michael acceptors having various types of α-substituents in a single catalyst system is achieved for the first time, demonstrating the utility of the present catalyst system for the construction of 1,3-nonadjacent stereogenic centers.