Irregularities in the Effect of Potassium Phosphate in Ynamide Synthesis

The yields of ynamides using Hsung′s second generation protocol depend substantially on the quality of K3PO4. Samples of K3PO4 from different suppliers were investigated by various techniques, revealing that the use of pure and anhydrous K3PO4 provides higher ynamide yields in comparison to samples contaminated with hydrates (K3PO4·1.5H2O and K3PO4·7H2O). With high quality K3PO4, a number of ynamides were synthesized in yields of 52−91%. In addition, we report that ynamides can undergo regioselective hydroamination with carbamates.