Enantioselective Decarboxylative Mannich Reaction Of Beta-Keto Acids With C-Alkynyl N-Boc N,O-Acetals: Access To Chiral Beta-Keto Propargylamines

The chiral keto-substituted propargylamines are an essential class of multifunctional compounds in the field of organic and pharmaceutical synthesis and have attracted considerable attention, but the related synthetic approaches remain limited. Therefore, a concise and efficient method for the enantioselective synthesis of beta-keto propargylamines via chiral phosphoric acid-catalyzed asymmetric Mannich reaction between beta-keto acids and C-alkynyl N-Boc N,O-acetals as easily available C-alkynyl imine precursors has been demonstrated here, affording a broad scope of beta-keto N-Boc-propargylamines in high yields (up to 97%) with generally high enantioselectivities (up to 97 : 3 er).