Chiral β-Keto Propargylamine Synthesis via Enantioselective Mannich Reaction of Enamides with C-Alkynyl N-Boc N,O-Acetals.

Propargylamines are an important class of compounds in organic synthesis and drug discovery, yet the synthesis of chiral β-keto propargylamines remains underdeveloped. Herein, we describe a streamlined and general enantioselective Mannich reaction of enamides with C-alkynyl N-Boc N,O-acetals, which serve as readily available C-alkynyl imine precursors, to access a broad range of chiral β-keto N-Boc-propargylamines bearing single stereogenic centers in high yields (up to 98%) and in high enantioselectivities (up to 95% ee).