Editing Stereochemistry (section)

==History==
In 1815, [[Jean-Baptiste Biot]]'s observation of optical activity marked the beginning of organic stereochemistry history. He observed that organic molecules were able to rotate the plane of polarized light in a solution or in the gaseous phase.<ref name=":0">{{Cite book |last=Nasipuri |first=D |title=Stereochemistry of Organic Compounds Principles and Applications |publisher=New Delhi: New Age International |year=2021 |isbn=978-93-89802-47-4 |edition=4th |pages=1}}</ref> Despite Biot's discoveries, [[Louis Pasteur]] is commonly described as the first stereochemist, having observed in 1842 that [[Salt (chemistry)|salt]]s of [[tartaric acid]] collected from [[wine]] production vessels could rotate the plane of [[polarized light]], but that salts from other sources did not. This was the only physical property that differed between the two types of tartrate salts, which is due to [[optical isomerism]]. In 1874, [[Jacobus Henricus van 't Hoff]] and [[Joseph Le Bel]] explained optical activity in terms of the tetrahedral arrangement of the atoms bound to carbon. Kekulé explored tetrahedral models earlier, in 1862, but never published his work; Emanuele Paternò probably knew of these but was the first to draw and discuss three dimensional structures, such as of [[1,2-dibromoethane]] in the ''Giornale di Scienze Naturali ed Economiche'' in 1869.<ref>{{Cite journal|last1=Paternò|first1=Emanuele|date=1869 |title=Intorno all'azione del percloruro di fosforo sul clorale|journal=Giorn. Sci. Nat. Econ.|volume=5 |pages=117–122|url=https://books.google.com/books?id=J00_AAAAcAAJ&pg=PA117}}</ref> The term "chiral" was introduced by [[William Thomson, 1st Baron Kelvin|Lord Kelvin]] in 1904. [[Arthur Robertson Cushny]], a Scottish Pharmacologist, first provided a clear example in 1908 of a bioactivity difference between enantiomers of a chiral molecule viz. (−)-Adrenaline is two times more potent than the (±)- form as a vasoconstrictor and in 1926 laid the foundation for chiral pharmacology/stereo-pharmacology<ref>{{Cite journal|last=Smith|first=Silas W.|date=2009-05-04|title=Chiral Toxicology: It's the Same Thing…Only Different|journal=Toxicological Sciences|volume=110|issue=1|pages=4–30|doi=10.1093/toxsci/kfp097 |pmid=19414517|issn=1096-6080|doi-access=free}}</ref><ref>{{Cite journal|last1=Patočka|first1=Jiří |last2=Dvořák |first2=Aleš|date=2004-07-31|title=Biomedical aspects of chiral molecules|journal=Journal of Applied Biomedicine|volume=2|issue=2|pages=95–100|doi=10.32725/jab.2004.011|doi-access=free}}</ref> (biological relations of optically isomeric substances). Later in 1966, the Cahn–Ingold–Prelog nomenclature or Sequence rule was devised to assign absolute configuration to [[stereogenic]]/chiral center (R- and S- notation) <ref>{{Cite journal |last1=Cahn|first1=R. S.|last2=Ingold|first2=Christopher |last3=Prelog|first3=V.|date=April 1966|title=Specification of Molecular Chirality|journal=Angewandte Chemie International Edition in English|volume=5|issue=4 |pages=385–415|doi=10.1002/anie.196603851 |issn=0570-0833}}</ref> and extended to be applied across olefinic bonds (E- and Z- notation).