# Chirality timeline

Chirality timeline presents a timeline of landmark events that unfold the developments happened in the field of chirality.
Many molecules come in two forms that are mirror images of each other, just like our hands. This type of molecule is called chiral. In nature, one of these forms is usually more common than the other. In our cells, one of these mirror images of a molecule fits "like a glove," while the other may be harmful.
In nature, molecules with chirality include hormones, DNA, antibodies, and enzymes. For example, (R)-limonene smells like oranges, while (S)-limonene smells like lemons. Both molecules have the same chemical formula, but their spatial orientations are different, which makes a big difference in their biological properties. Chiral molecules in the receptors in our noses can tell the difference between these things. Chirality affects biochemical reactions, and the way a drug works depends on what kind of enantiomer it is. Many drugs are chiral and it is important that the shape of the drug matches the shape of the cell receptor it is meant to affect. Mismatching will make the drug less effective, which could be a matter of life and death, as happened with thalidomide in the 1960s.
It has long been known that structural factors, particularly chirality and stereochemistry, have a big impact on pharmacological efficacy and pharmacokinetic behavior. Since more than a century ago, pertinent information pertaining to chirality has been accumulating in numerous fields, in particular, physics, chemistry and biology, at an accelerated rate, giving rise to more comprehensive and in-depth reasoning, conceptions, and ideas. This page offers a chronology of significant contributions that have been made in the journey of chirality [1809 to 2021].

## Chirality timeline

Timeline of contributions in the field of chirality :
| Year | Name | Country | Contribution/Achievement | Ref |
| 1809 | Étienne-Louis Malus | France | Discovery of plane polarized light; Origin of stereochemistry | |
| 1811 | Dominique François Jean Arago | France | Showed how cut crystals change the plane of polarized light | |
| 1812 | Jean-Baptiste Biot | France | Found that a quartz plate cut at a right angle to its crystal axis rotates the plane of polarized light by an angle that is proportional to the thickness of the plate. This is the phenomenon of optical rotation | |
| 1815 | Jean-Baptiste Biot | France | Applied these ideas to organic substances, like oil of turpentine, sugar, camphor, and tartaric acid (solutions of solids) | |
| 1820 | Eilhard Mitscherlich | German | Discovery of the phenomenon of crystallographic isomorphism. Correlated the similarity of crystal shapes with an analogy in chemical composition, reported that sodium ammonium salts of (+)-tartaric acid and racemic acids are completely isomorphous and are identical in all aspects except in optical activity | |
| 1848 | Louis Pasteur | France | The racemic sodium ammonium salt of tartaric acid was crystallized, and two different types of crystals were found. First, enantiomers were physically separated | |
| 1857 | Louis Pasteur | France | Made the first observation of enantioselectivity in living things | |
| 1874 | Jacobus Henricus van't Hoff | Netherlands | Outlined the connection between a molecule's three-dimensional structure, its optical activity, and the idea of asymmetric carbon. Proposed a stereochemical theory of isomerism based on the three-dimensional structure of molecules. Van't Hoff, who won the first Nobel Prize in Chemistry in 1901, for discovery of the laws of chemical dynamics and osmotic pressure in solutions" | |
| 1874 | Joseph Achille Le Bel | France | Used asymmetry arguments and talked about the asymmetry of the molecules as a whole instead of the asymmetry of each carbon atom. Le Bel's thought could be considered as the general theory of stereoisomerism. | |
| 1875 | Jacobus Henricus van't Hoff | Netherlands | Predicted allenes' stereoisomerism, but it wasn't seen in the lab until 1935 | |
| 1890 | Hermann Emil Louis Fischer | German | Imagined the fit between the enzyme and the substrate as a lock and key mechanism. He made Fischer projections to show their three-dimensional structures. He was awarded the second Nobel Prize in chemistry, 1902 "in recognition of the extraordinary services he has rendered by his work on sugar and purine syntheses.". | |
| 1890 | Poulson | | Contributions to the knowledge of the pharmacological group of cocaine | |
| 1894 | Ehrlich and Einhorn. | | Physiological and toxicological significance of chiral compounds; found (+)-cocaine was more active, started working faster, and lasted less time than (-)-cocaine. | |
| 1903 | Arthur Robertson Cushny | United Kingdom | Described how atropine and (-)-hyoscyamine work differently on the papillary, cardiac, and salivary systems and how they affect the spinal cord of a frog; First, gave clear examples of how the biological activity of two enantiomers of a chiral molecule can be different. | |
| 1904 | Pictet. and Rotschy | | Described the differences in nicotine isomers' toxic doses | |
| 1904 | William Thomson | British | The term "chiral" was first used and introduced. Later, Lord Kelvin was made a peer. | |
| 1908 | Abderhalden. and Müller | | Described (-)- and (+)-epinephrine have very different effects on blood pressure. | |
| 1910 | Grove | | Nicotine isomers have different levels of toxicity. | |
| 1918 | Frey | | Reported the isomer of quinine - quinidine, to be more effective in treating dysrhythmias. | |
| 1933 | Easson and Stedman | | Advanced a thee-point attachment model to explain chiral recognition process between the drug (with a single center of asymmetry) and the receptor or enzyme active site | |
| 1957 1958 | Lancelot Law Whyte | Scotland | Rediscovered term chiral | , |
| 1965 | Kurt Martin Mislow | United States | Firmly reintroduced the term chirality into stereochemical literature; German-born American organic chemist | |
| 1956/1966 | Robert Sidney Cahn | British | Devised R/S and E/Z notations; Cahn–Ingold–Prelog priority rules | |
| 1956/1966 | Christopher Kelk Ingold | British | Co-author of Cahn–Ingold–Prelog priority rules; Did groundbreaking work (between 1920-30s) on reaction mechanisms and the electronic structure of organic compounds | |
| 1956/1966 | Vladimir Prelog | Sarajevo | Co-author of the Cahn–Ingold–Prelog priority rules | |
| 1975 | Vladimir Prelog | Sarajevo | Nobel prize in chemistry for his research into the stereochemistry of organic molecules and reaction | |
| 1975 | John Cornforth | Australia | Awarded Nobel prize for his work on the stereochemistry of enzyme-catalyzed reactions | |
| 2001 | William Standish Knowles | United States | Won Nobel prize in chemistry in 2001 for his work on the development of catalytic asymmetric synthesis (chirally catalyzed hydrogenation reactions | |
| 2001 | Ryōji Noyori | Japan | Won Nobel prize in chemistry in 2001 for his work on the development of catalytic asymmetric synthesis (chirally catalyzed hydrogenation reactions) | |
| 2001 | Karl Barry Sharpless | United States | Won Nobel prize in chemistry in 2001 for his work on the development of catalytic asymmetric synthesis (chirally catalyzed oxidation reactions) | |
| 2021 | Benjamin List | German | Awarded Nobel Prize in Chemistry in 2021 for his work on the development of asymmetric organocatalysis | |
| 2021 | David MacMillan | United Kingdom United States | Awarded Nobel Prize in Chemistry in 2021 for his work on the development of asymmetric organocatalysis | |