and unsaturated substrates. A classic application is the Favorskii reaction. Illustrative is the sequence shown below, ethyl propiolate is deprotonated by n-butyllithium to give the corresponding acetylide. This acetylide adds to the carbonyl center of cyclopentanone. Hydrolytic workup liberate the alkynyl alcohol. Coupling reactions Acetylides are sometimes intermediates in coupling reactions. Examples include Sonogashira coupling, Cadiot-Chodkiewicz coupling, Glaser coupling and Eglinton coupling. Hazards Some acetylides are notoriously explosive. Formation of acetylides poses a risk in handling of gaseous acetylene in presence of metals such as mercury, silver or copper, or alloys with their high content (brass, bronze, silver solder). See also Ethynyl Ethynyl radical Diatomic carbon (neutral C2) Acetylenediol References Anions Functional groups