Alkynylation

In organic chemistry, alkynylation is an addition reaction in which a terminal alkyne (−C≡CH) is added to a carbonyl group (C=O) to form an α-alkynyl alcohol (R2C(−OH)−C≡C−R).

[1][3][5] Chemist Walter Reppe coined the term ethynylation during his work with acetylene and carbonyl compounds.

[18] Grignard reagents of acetylene or alkynes can be used to perform alkynylations on compounds that are liable to polymerization reactions via enolate intermediates.

However, substituting lithium for sodium or potassium acetylides accomplishes similar results, often giving this route little advantage over the conventional reaction.

[1] Chemist Walter Reppe pioneered catalytic, industrial-scale ethynylations using acetylene with alkali metal and copper(I) acetylides:[1] These reactions are used to manufacture propargyl alcohol and butynediol.