Editing Permethrin (section)

== Stereochemistry ==
Permethrin has four [[Stereoisomerism|stereoisomers]] (two [[enantiomer]]ic pairs), arising from the two [[stereocenter]]s in the [[cyclopropane]] ring. The ''[[Cis-trans isomerism|trans]]'' enantiomeric pair is known as transpermethrin. (1''R'',3''S'')-''trans'' and (1''R'',3''R'')-''cis'' enantiomers are responsible for the insecticidal properties of permethrin.<ref>{{cite journal | vauthors = Dornetshuber J, Bicker W, Lämmerhofer M, Lindner W, Karwan A, Bursch W |title=Impact of stereochemistry on biological effects of permethrin: induction of apoptosis in human hepatoma cells (HCC-1.2) and primary rat hepatocyte cultures |journal=BMC Pharmacology |date=14 November 2007 |volume=7 |issue=Supplement 2 |page=A65 |doi=10.1186/1471-2210-7-S2-A65 |issn=1471-2210 |quote=Stereochemistry plays a crucial role in determining the toxicological profile of many chiral xenobiotics, e.g. the insecticidal action of mixtures containing the four stereoisomers of permethrin is essentially brought about by the (1R, cis)- and (1R, trans)-forms.|doi-access=free }}</ref>

<div class="skin-invert-image"><gallery widths="240" heights="80" perrow="2">
(1S)-trans-permethrin.svg|(1''S'',3''R'')-''trans'' enantiomer
(3S)-trans-permethrin.svg|(1''R'',3''S'')-''trans'' enantiomer
Cis-permethrin-A.svg|(1''S'',3''S'')-''cis'' enantiomer
Cis-permethrin-B.svg|(1''R'',3''R'')-''cis'' enantiomer
</gallery></div>