Oxidative Aminocarbonylation of Terminal Alkynes for the Synthesis of Alk-2-ynamides by Using Palladium-on-Carbon as Efficient, Heterogeneous, Phosphine-Free, and Reusable Catalyst

Palladium-on-carbon (Pd/C)-catalyzed oxidative aminocarbonylations of alk-1-ynes with secondary amines provide the corresponding alk-2-ynamides in a good to excellent yields. This new methodology is applicable for the synthesis of a wide range of biologically active alk-2-ynamide derivatives. The developed protocol avoids the use of phosphine ligands, with an additional advantage of palladium catalyst recovery and reuse for up to four consecutive cycles.