In some cases, intramolecular coupling of terminal alkynes may also occur to produce cyclic compounds, if the resulting ring is not highly strained. For example, the synthesis of macrocyclic lactone, exaltolide, that is partly responsible for the sweet odour of the angelica root, could accomplished with high yield.

Coupling of monosubstituted acetylene with 1-bromoalkyene can be performed to afford hetero coupled product in good yield.

9.3.4 Acyloin Condensation

Aliphatic ester reacts with molten sodium in hot xylene to yield the disodium derivative of acyloin which is converted into acyloin in the presence of acid. The reaction is to be carried out under nitrogen because acyloins and their anions are prone to undergo oxidation with air.