Organocatalytic Enantioselective α-Amination by Conjugate Addition of 5H-Thiazol-4-ones to Arylazocarboxylates: Access to ChiralN,S-acetals

A chiral phosphoric acid catalyzed stereoselective Michael addition of 5H-thiazol-4-ones to arylazocarboxylates was developed for the construction of optically activeN,S-acetal frameworks. Both 1-naphthylazocarboxylates and phenylazocarboxylates were compatible to afford a series of 1,4-adducts in generally high yields and enantioselectivities. Notably, the catalytic protocol enables the formation ofN,S-acetals featuring thiazol-4-one skeleton.