Editing Alkyne (section)

===Dehydrohalogenation and related reactions===
Alkynes are prepared from 1,1- and 1,2-[[dihaloalkane]]s by double [[dehydrohalogenation]]. The reaction provides a means to generate alkynes from alkenes, which are first [[halogenated]] and then dehydrohalogenated. For example, [[phenylacetylene]] can be generated from [[styrene]] by [[bromination]] followed by treatment of the resulting of 1,2-dibromo-1-phenylethane with [[sodium amide]] in [[ammonia]]:<ref>{{OrgSynth | doi= 10.15227/orgsyn.030.0072| volume= 30 | page = 72 | year = 1950 | title = Phenylacetylene | author = Kenneth N. Campbell, Barbara K. Campbell}}</ref><ref>{{cite journal |doi=10.15227/orgsyn.059.0010|title=Alkyness via Phase Transfer-Catalyzed Dehydrohalogenatiion: Propiolaldehyde Diethyl Acetal|journal=Organic Syntheses|year=1979|volume=59|page=10|author=A. Le Coq and A. Gorgues}}</ref>

:[[File:Phenylacetylene prepn.png|350px]]

Via the [[Fritsch–Buttenberg–Wiechell rearrangement]], alkynes are prepared from [[vinyl bromide]]s. Alkynes can be prepared from [[aldehyde]]s using the [[Corey–Fuchs reaction]] and from aldehydes or [[ketone]]s by the [[Seyferth–Gilbert homologation]].

[[Vinyl halide]]s are susceptible to dehydrohalogenation.