chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...

, a multi-component reaction (or MCR), sometimes referred to as a "Multi-component Assembly Process" (or MCAP), is a

chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...

where three or more compounds react to form a single product. By definition, multicomponent reactions are those reactions whereby more than two reactants combine in a sequential manner to give highly selective products that retain majority of the atoms of the starting material.

History and Types Multicomponent Reactions

Multicomponent reactions have been known for over 150 years. The first documented multicomponent reaction was the Strecker synthesis of α-amino cyanides in 1850 from which α-amino acids could be derived. A multitude of MCRs exist today, of which the isocyanide based MCRs are the most documented. Other MCRs include free-radical mediated MCRs, MCRs based on organoboron compounds and metal-catalyzed MCRs. Isocyanide based MCRs are most frequently exploited because the isocyanide is an extraordinary functional group. It is believed to exhibit resonance between its tetravalent and divalent carbon forms. This induces the isocyanide group to undergo both electrophilic and nucleophilic reactions at the CII atom, which then converts to the CIV form in an exothermic reaction. The occurrence of isocyanides in natural products has also made it a useful functional group. The two most important isocyanide-based multicomponent reactions are the Passerini 3-component reaction to produce α-acyloxy carboxamides and the Ugi 4-component reaction, which yields the α-amino carboxamides. Examples of three component reactions: *

Alkyne trimerisation In organic chemistry, an alkyne trimerisation is a +2+2nbsp; cycloaddition reaction in which three alkyne units () react to form a benzene ring. The reaction requires a metal catalyst. The process is of historic interest as well as being applic ...

Biginelli reaction The Biginelli reaction is a multiple-component chemical reaction that creates 3,4-dihydropyrimidin-2(1''H'')-ones 4 from ethyl acetoacetate 1, an aryl aldehyde (such as benzaldehyde 2), and urea 3. It is named for the Italian chemist Pietro Bigi ...

Bucherer–Bergs reaction The Bucherer–Bergs reaction is the chemical reaction of carbonyl compounds (aldehydes or ketones) or cyanohydrins with ammonium carbonate and potassium cyanide to give hydantoins. The reaction is named after Hans Theodor Bucherer. ''Overall Rea ...

Gewald reaction The Gewald reaction is an organic reaction involving the condensation of a ketone (or aldehyde when R2 = H) with a α-cyanoester in the presence of elemental sulfur and base to give a poly-substituted 2-amino-thiophene. The reaction is named ...

* Grieco three-component coupling *

Hantzsch pyridine synthesis The Hantzsch pyridine synthesis or Hantzsch dihydropyridine synthesis is a multi-component organic reaction between an aldehyde such as formaldehyde, 2 equivalents of a β-keto ester such as ethyl acetoacetate and a nitrogen donor such as ammoni ...

Kabachnik–Fields reaction In organophosphorus chemistry, the Kabachnik–Fields reaction is a three-component organic reaction forming aminophosphonate, α-aminomethylphosphonates from an amine, a carbonyl compound, and a phosphite ester, dialkyl phosphonate, (RO)2P(O)H (tha ...

Mannich reaction In organic chemistry, the Mannich reaction is a three-component organic reaction that involves the amino alkylation of an acidic proton next to a carbonyl () functional group by formaldehyde () and a primary or secondary amine () or ammonia (). ...

Passerini reaction The Passerini reaction is a chemical reaction involving an isocyanide, an aldehyde (or ketone), and a carboxylic acid to form a α- acyloxy amide. This addition reaction is one of the oldest isocyanide-based multicomponent reactions (IMCR) and wa ...

Pauson–Khand reaction The Pauson–Khand reaction (or PKR or PK-type reaction) is a chemical reaction described as a 2+2+1.html" ;"title="/nowiki>2+2+1">/nowiki>2+2+1/nowiki> cycloaddition between an alkyne, an alkene and carbon monoxide to form a α,β-cyclopentenone. ...

Petasis reaction The Petasis reaction (alternatively called the Petasis borono–Mannich (PBM) reaction) is the multi-component reaction of an amine, a carbonyl, and a vinyl- or aryl-boronic acid to form substituted amines. Reported in 1993 by Nicos Petasis ...

Strecker amino acid synthesis The Strecker amino acid synthesis, also known simply as the Strecker synthesis, is a method for the synthesis of amino acids by the reaction of an aldehyde with ammonia in the presence of potassium cyanide. The condensation reaction yields an α- ...

Ugi reaction The Ugi reaction is a multi-component reaction in organic chemistry involving a ketone or aldehyde, an amine, an isocyanide and a carboxylic acid to form a bis-amide. The reaction is named after Ivar Karl Ugi, who first reported this reaction in 1 ...

Asinger reaction The Asinger-reaction (sometimes referred to as the Asinger-4 component reaction or A-4CR for short) is a multicomponent reaction for the synthesis of 3-thiazolines and other related heterocycles. It is named after Friedrich Asinger who first reporte ...

A3 coupling reaction The A3 coupling (also known as A3 coupling reaction or the aldehyde-alkyne-amine reaction), coined by Prof. Chao-Jun Li of McGill University, is a type of multicomponent reaction involving an aldehyde, an alkyne and an amine which react to give a pr ...

The exact nature of this type of reaction is often difficult to assess, in

collision theory Collision theory is a principle of chemistry used to predict the rates of chemical reactions. It states that when suitable particles of the reactant hit each other with correct orientation, only a certain amount of collisions result in a percept ...

a simultaneous interaction of 3 or more different molecules is less likely resulting in a low

reaction rate The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit ...

. These reactions are more likely to involve a series of bimolecular reactions. New MCR's are found by building a

chemical library A chemical library or compound library is a collection of stored chemicals usually used ultimately in high-throughput screening or industrial manufacture. The chemical library can consist in simple terms of a series of stored chemicals. Each chemic ...

from

combinatorial chemistry Combinatorial chemistry comprises chemical synthetic methods that make it possible to prepare a large number (tens to thousands or even millions) of compounds in a single process. These compound libraries can be made as mixtures, sets of individua ...

or by combining existing MCR's. For example, a 7-component MCR results from combining the

with the

. MCR's are an important tool in new drug discovery. MCR's can often be extended into combinatorial, solid phase or flow syntheses for developing new lead structures of active agents.''Multicomponent reactions'' Thomas J. J. Müller (Editor
Thematic Series
in the Open Access

Beilstein Journal of Organic Chemistry The ''Beilstein Journal of Organic Chemistry'' is a peer-reviewed open-access scientific journal established in 2005. It is published by the Beilstein Institute for the Advancement of Chemical Sciences, a German non-profit foundation. The editor-in ...

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Multicomponent reactions

Presentation on Multicomponent Reactions
Chemical kinetics Chemical synthesis

History and Types Multicomponent Reactions

See also

References

External links