Editing Alkyne (section)

=== Alkylation and arylation of terminal alkynes ===
Terminal alkynes (RC≡CH, including acetylene itself) can be deprotonated by bases like [[Sodium amide|NaNH<sub>2</sub>]], [[N-Butyllithium|BuLi]], or [[Ethylmagnesium bromide|EtMgBr]] to give [[acetylide]] anions (RC≡C:<sup>–</sup>M<sup>+</sup>, M = Na, Li, MgBr) which can be alkylated by addition to carbonyl groups ([[Favorskii reaction]]), ring opening of epoxides, or S<sub>N</sub>2-type substitution of unhindered primary alkyl halides.

In the presence of transition metal catalysts, classically a combination of [[Bis(triphenylphosphine)palladium chloride|Pd(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>]] and [[Copper(I) iodide|CuI]], terminal acetylenes (RC≡CH) can react with aryl iodides and bromides (ArI or ArBr) in the presence of a secondary or tertiary amine like [[Triethylamine|Et<sub>3</sub>N]] to give arylacetylenes (RC≡CAr) in the [[Sonogashira reaction]].

The availability of these reliable reactions makes terminal alkynes useful building blocks for preparing internal alkynes.