In 2020, a group of scientists posted an article called ‘Acetylene Group, Friend or Foe in Medicinal Chemistry’. In our opinion, this is a very substantial work, that shows the advantages and disadvantages of the ethynyl group in medicinal chemistry, and the impact of this group on chemical biology approaches.
There are many roles that this structural feature can play in drug activity, which include potency enhancement (by a complementary fit into a receptor binding pocket), reactive warhead (for irreversible inhibition of a target protein), nonpolar linear rigid spacer (to direct pharmacophore appendages in a favorable geometry), bioisostere to a wide range of functionalities, and modulation of DMPK profile.
These values help ethynyl groups to be broadly exploited in drug discovery and development.
Based on the article, we prepared a set of ethynyl-containing compounds, that might become a great start for your research!