Organic Reaction

Information about Organic Reaction

The Claisen rearrangement

Organic reactions are chemical reactions involving organic compounds.^[1] The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions and redox reactions. In organic synthesis, organic reactions are used in the construction of new organic molecules. The production of many man-made chemicals such as drugs, plastics, food additives, fabrics depend on organic reactions.

The oldest organic reactions are combustion of organic fuels and saponification of fats to make soap. Modern organic chemistry starts with the WÃ¶hler synthesis in 1828. In the history of the Nobel Prize in Chemistry awards have been given for the invention of specific organic reactions such as the Grignard reaction in 1912, the Diels-Alder reaction in 1950, the Wittig reaction in 1979 and olefin metathesis in 2005.

Classifications

Organic chemistry has a strong tradition of naming a specific reaction to its inventor or inventors and a long list of so-called named reactions exists, conservatively estimated at 1000. A very old named reaction is the Claisen rearrangement (1912) and a recent named reaction is the Bingel reaction (1993). When the named reaction is difficult to pronounce or very long as in the Corey-House-Posner-Whitesides reaction it helps to use the abbreviation as in the CBS reduction. The number of reactions hinting at the actual process taking place is much smaller, for example the ene reaction or aldol reaction.

Another approach to organic reactions is by type of organic reagent, many of them inorganic, required in a specific transformation. The major types are oxidizing agents such as osmium tetroxide, reducing agents such as Lithium aluminium hydride, bases such as lithium diisopropylamide and acids such as sulfuric acid.

Fundamentals

Factors governing organic reactions are essentially the same as that of any chemical reaction. Factors specific to organic reactions are those that determine the stability of reactants and products such as conjugation, hyperconjugation and aromaticity and the presence and stability of reactive intermediates such as free radicals, carbocations and carbanions.

An organic compound may consist of many isomers. Selectivity in terms of regioselectivity, diastereoselectivity and enantioselectivity is therefore an important criterion for many organic reactions. The stereochemistry of pericyclic reactions is governed by the Woodward-Hoffmann rules and that of many elimination reactions by the Zaitsev's rule.

Organic reactions are important in the production of pharmaceuticals. In a 2006 review ^[2] it was estimated that 20% of chemical conversions involved alkylations on nitrogen and oxygen atoms, another 20% involved placement and removal of protective groups, 11% involved formation of new carbon-carbon bond and 10% involved functional group interconversions.

Organic reactions by mechanism

There is no limit to the number of possible organic reactions and mechanisms. However, certain general patterns are observed that can be used to describe many common or useful reactions. Each reaction has a stepwise reaction mechanism that explains how it happens, although this detailed description of steps is not always clear from a list of reactants alone. Organic reactions can be organized into several basic types. Some reactions fit into more than one category. For example, some substitution reactions follow an addition-elimination pathway. This overview isn't intended to include every single organic reaction. Rather, it is intended to cover the basic reactions.

Addition reactions include such reactions as halogenation, hydrohalogenation and hydration. The main addition reactions are:

Elimination reactions include processes such as dehydration and are found to follow a E1, E2 or E1cB reaction mechanism
Substitution reactions are divided into:

nucleophilic aliphatic substitution with SN1, SN2 and SNi reaction mechanisms
nucleophilic aromatic substitution or NAS
nucleophilic acyl substitution
electrophilic substitution or ES
electrophilic aromatic substitution or EAS
radical substitution or RS

Organic redox reactions are redox reactions specific to organic compounds and are very common.
Rearrangement reactions are divided into:

In Condensation reactions a small molecule, usually water, is split off when two reactants combine in a chemical reaction. The opposite reaction, when water is consumed in a reaction, is called hydrolysis. Many Polymerization reactions are derived from organic reactions. They are divided into addition polymerizations and step-growth polymerizations.

Organic reactions by functional groups

Functional group	Preparation	Reactions
Acyl halides:	preparation	reactions
Aldehydes:	preparation	reactions
Acyloins:	preparation	reactions
*Alkanes:	preparation	reactions
Alkenes	preparation	reactions
Alkynes	preparation	reactions
Alkyl halides	preparation	reactions
Alcohols	preparation	reactions
Arene compounds	preparation	reactions
Azides	preparation	reactions
Aziridines	preparation	reactions
Amides	preparation	reactions
Amines	preparation	reactions
Carboxylic acids	preparation	reactions
Cyclopropanes	preparation	reactions
Diols	preparation	reactions
Esters	preparation	reactions
Ethers	preparation	reactions
Epoxide:	preparation	reactions
Haloketones	preparation	reactions
Imines	preparation	reactions
Isocyanates	preparation	reactions
Ketones	preparation	reactions
Lactams	preparation	reactions
Nitriles	preparation	reactions
Nitrites	preparation	reactions
Phenols	preparation	reactions

Organic reactions can be categorized based on the type of functional group involved in the reaction as a reactant and the functional group that is formed as a result of this reaction. For example in the Fries rearrangement the reactant is an ester and the reaction product an alcohol.

An overview of functional groups with their preparation and reactivity is presented on the right:

Other organic reaction classification

In heterocyclic chemistry, organic reactions are classified by the type of heterocycle formed with respect to ring-size and type of heteroatom. See for instance the chemistry of indoles.

Organic reactions can also be classified by the type of bond to carbon with respect to the element involved. More reactions are found in organosilicon chemistry, organosulfur chemistry, organophosphorus chemistry and organofluorine chemistry. With the introduction of carbon-metal bonds the field crosses over to organometallic chemistry.

CNa

CSc

CCr

CMn

CFe

CCo

CGa

CRb

CSr

CZr

CNb

CMo

CTc

CRu

CRh

CPd

CAg

CCd

CIn

CSn

CSb

CTe

CCs

CBa

CHf

CTa

CRe

COs

CIr

CPt

CAu

CHg

CTl

CPb

CBi

CPo

CAt

Uub

Uut

Uuq

Uup

Uuh

Uus

Uuo

↓

**Chemical bonds to carbon**
Core organic chemistry	many uses in chemistry.
Academic research no widespread use	Bond unknown / not assessed.

External links

References

1. ^ Strategic Applications of Named Reactions in Organic Synthesis Laszlo Kurti, Barbara Czako Academic Press (March 4, 2005) ISBN 0-12-429785-4
2. ^ Analysis of the reactions used for the preparation of drug candidate molecules John S. Carey, David Laffan, Colin Thomson and Mike T. Williams Org. Biomol. Chem., 2006, 4, 2337 - 2347, doi:10.1039/b602413k

• • [ e] Topics in Organic Reactions
Addition reaction - Elimination reaction - Polymerization - - Rearrangement reaction - Redox reaction - Regioselectivity - Stereoselectivity - Substitution reaction List of organic reactions

• • [ e] Concepts in organic chemistry
Aromaticity, Covalent bonding, Functional groups, Nomenclature, Organic compounds, Organic reactions, Organic synthesis, Publications, Spectroscopy, Stereochemistry, List of organic compounds

chemical reaction is a process that results in the interconversion of chemical substances.^[1] The substance or substances initially involved in a chemical reaction are called reactants.
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organic compounds]] An organic compound is any member of a large class of chemical compounds whose molecules contain carbon; for historical reasons discussed below, a few types of compounds such as carbonates, carbon oxides and cyanides, as well as elemental carbon are
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Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may
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An addition reaction, in chemistry, is in its simplest terms an organic reaction where two or more molecules combine to form a larger one.

There are two main types of polar addition reactions:

Electrophilic addition
Nucleophilic addition

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An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism ^[1]. Either the unsaturation of the molecule increases (as in most organic elimination reactions) or the valence of an atom
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In a substitution reaction, a functional group in a particular chemical compound is replaced by another group.

In organic chemistry, the electrophilic and nucleophilic substitution reactions are of prime importance.
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In organic chemistry, a pericyclic reaction is a type of organic reaction wherein the transition state of the molecule has a cyclic geometry, and the reaction progresses in a concerted fashion. Pericyclic reactions are usually rearrangement reactions.
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A rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. Often a substituent moves from one atom to another atom in the same molecule.
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Organic reductions or organic oxidations or organic redox reactions are redox reactions that take place with organic compounds. In organic chemistry oxidations and reductions are different from ordinary redox reactions because many reactions carry the name but do not
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Organic synthesis is the construction of organic molecules via chemical processes. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has developed into one of the most important aspects of
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Combustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames.
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Saponification is the hydrolysis of an ester under basic conditions to form an alcohol and the salt of a carboxylic acid. Saponification is commonly used to refer to the reaction of a metallic alkali (base) with a fat or oil to form soap.
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The WÃ¶hler synthesis is the conversion of ammonium cyanate into urea ^[1]. This chemical reaction was discovered in 1828 by Friedrich WÃ¶hler in an attempt to synthesize ammonium cyanate itself and is considered the starting point of modern organic chemistry.
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Nobel Prize in Chemistry (Swedish: Nobelpriset i kemi) is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the six Nobel Prizes. The first prize was awarded in 1901.
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The Grignard reaction, named for the French chemist FranÃ§ois Auguste Victor Grignard, is an organometallic chemical reaction involving alkyl- or aryl-magnesium halides, also called Grignard reagents, with electrophiles.
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The Diels-Alder reaction is an organic chemical reaction (specifically, a cycloaddition) between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system.
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The Wittig reaction is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide (often called a Wittig reagent) to give an alkene and triphenylphosphine oxide.
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Olefin metathesis or transalkylidenation (in some literature, a disproportionation) is an organic reaction which involves redistribution of olefinic (alkene) bonds.^[1]
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This page aims to list well-known reactions and reagents in organic chemistry. It is organized in alphabetical order. You may also find it useful to browse .

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