Application of Ynamides in the Synthesis of 2-Amidoindoles
摘要:
A Pd-catalyzed, one-pot, two-step synthesis of 2-amidoindoles from ynamides and o-lodoanilines Is reported. A key highlight of this sequence is that after the Sonogashira reaction, intramolecular cyclization to the indole occurs spontaneously without activation of the alkyne.
The yields of ynamides using Hsung's second generation protocol depend substantially on the quality of K3PO4. 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 center dot 1.5H(2)O and K3PO4 center dot 7H(2)O). 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.