Editing Alkene (section)

===From alkynes===
Reduction of [[alkyne]]s is a useful method for the [[stereoselectivity|stereoselective]] synthesis of disubstituted alkenes. If the ''cis''-alkene is desired, [[hydrogenation]] in the presence of [[Lindlar's catalyst]] (a heterogeneous catalyst that consists of palladium deposited on calcium carbonate and treated with various forms of lead) is commonly used, though hydroboration followed by hydrolysis provides an alternative approach. Reduction of the alkyne by [[sodium]] metal in liquid [[ammonia]] gives the ''trans''-alkene.<ref name="ZweifelNantz">{{cite book | last1 = Zweifel | first1 = George S. |last2=Nantz |first2=Michael H.| title = Modern Organic Synthesis: An Introduction  | url = https://archive.org/details/modernorganicsyn00zwei | url-access = limited |  publisher = W. H. Freeman | year = 2007 | pages = [https://archive.org/details/modernorganicsyn00zwei/page/n373 366] | isbn = 978-0-7167-7266-8 }}</ref>

[[Image:AlkyneToAlkene.png|600px|center|Synthesis of ''cis''- and ''trans''-alkenes from alkynes]]

For the preparation multisubstituted alkenes, [[carbometalation]] of alkynes can give rise to a large variety of alkene derivatives.