Stereoselective metal-free synthesis of β-amino thioesters with tertiary and quaternary stereogenic centers.

β-Amino thioesters are important natural building blocks for the synthesis of numerous bioactive molecules. An organocatalyzed Mannich reaction was developed which provides direct and highly stereoselective access to acyclic β(2)- and β(2,3,3)-amino thioesters with adjacent tertiary and quaternary stereocenters. Mechanistic studies showed that the stereochemical course of the reaction can be controlled by the choice of the substrates.