The 1,3-enyne moiety is an important structural unit for biologically active and natural compounds. It can be derived from vinylic systems and terminal acetylenes by using a configuration-retention stereospecific procedure such as the Sonogashira reaction. Vinyl iodides are the most reactive vinyl halides to Pd oxidative addition, and their use is therefore most frequent for Sonogashira cross-coupling reactions due to the usually milder conditions employed. Some examples include:
*The coupling of 2-iodoprop-2-en-1-ol with a wide range of acetylenes.
*The preparation of alk-2-ynylbuta-1,3-dienes from the cross-coupling of a diiodide and phenylacetylene, as shown below.