Illustrated Glossary of Organic Chemistry

Wurtz reaction (Wurtz coupling): A reaction in which two molecules of an alkyl halide are coupled (joined) in the presence of Na, Mg, or other reactive metals.

2 CH3(CH2)15I	Mg ether	CH3(CH2)30CH3	+	MgI2
Cetyl iodide		n-Dotriacontane

Wurtz reaction of cetyl iodide with Mg in ether gives n-dotriacontane in good yield.

CH3CH2CH2CH2I	+	CH3CH2CH2I	2 Na	CH3CH2CH2CH2CH2CH2CH2CH3	+	CH3CH2CH2CH2CH2CH2CH3	+	CH3CH2CH2CH2CH2CH3	+   NaI
1-Iodobutane		1-Iodopropane		n-Octane		n-Heptane		n-Hexane

A Wurtz coupling between two alkyl halides with different alkyl groups is usually not very efficient. Such reactions give a statistical mixture of all three possible products. For example, Wurtz coupling of 1-iodobutane with 1-iodopropane gives equal amounts of n-octane (produced from two molecules of 1-iodobutane), n-heptane (from one molecule of 1-iodobutane and one molecule of 1-iodopropane), and n-hexane (from two molecules of 1-iodopropane).