Editing Enamine (section)

{{Short description|Class of chemical compounds}}
[[File:Enamine-2D-skeletal.svg|thumb|150px|The general structure of an enamine]]
An '''enamine''' is an [[unsaturated compound]] derived by the condensation of an [[aldehyde]] or [[ketone]] with a secondary [[amine]].<ref>{{cite book | author = Clayden, Jonathan | title = Organic chemistry | publisher = Oxford University Press | location = Oxford, Oxfordshire | year = 2001 | isbn = 978-0-19-850346-0 | url = https://archive.org/details/organicchemistry00clay_0 | url-access = registration }}</ref><ref>{{March6th}}</ref> Enamines are versatile intermediates.<ref>Enamines: Synthesis: Structure, and Reactions, Second Edition, Gilbert Cook (Editor).  1988, Marcel Dekker, NY.  {{ISBN|0-8247-7764-6}}</ref><ref>{{OrgSynth|author=R. B. Woodward, I. J. Pachter, and M. L. Scheinbaum |year=1974|title=2,2- (Trimethylenedithio)cyclohexanone|volume=54|pages=39|collvol=5|collvolpages=1014|prep=CV6P1014}}</ref>

The word "enamine" is derived from the affix ''en''-, used as the suffix of [[alkene]], and the root ''amine''. This can be compared with [[enol]], which is a functional group containing both alkene (''en''-) and [[Alcohol (chemistry)|alcohol]] (-''ol''). Enamines are considered to be nitrogen analogs of enols.<ref>[http://pharmaxchange.info/press/2011/04/imines-and-enamines-nitrogen-analogs-of-enols-and-enolates/ Imines and Enamines | PharmaXChange.info]</ref>

If one or both of the nitrogen substituents is a hydrogen atom it is the [[tautomer]]ic form of an [[imine]]. This usually will rearrange to the imine; however there are several exceptions (such as [[aniline]]). The enamine-imine tautomerism may be considered analogous to the [[keto-enol tautomerism]]. In both cases, a hydrogen atom switches its location between the heteroatom (oxygen or nitrogen) and the second carbon atom.

Enamines are both good nucleophiles and good bases.  Their behavior as carbon-based nucleophiles is explained with reference to the following resonance structures.
:[[File:EnamineResonanceStructures.svg|thumb|center|Resonance structures for an enamine]]