In
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 convergent synthesis is a strategy that aims to improve the
efficiency
Efficiency is the often measurable ability to avoid wasting materials, energy, efforts, money, and time in doing something or in producing a desired result. In a more general sense, it is the ability to do things well, successfully, and without ...
of
multistep synthesis, most often in
organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
. In this type of synthesis several individual pieces of a complex molecule are synthesized in stage one, and then in stage two these pieces are combined to form the final product. In linear synthesis the overall
yield quickly drops with each reaction step:
:A → B → C → D
Suppose the yield is 50% for each reaction; the overall yield of D is only 12.5% from A.
In a convergent synthesis
:A → B (50%)
:C → D (50%)
:B + D → E (25%)
the overall yield of E (25%) looks much better. Convergent synthesis is applied in the synthesis of complex molecules and involves fragment coupling and independent synthesis. This technique is more useful if the compound is large and symmetric, where at least two aspects of the molecule can be formed separately and still come together.
Examples:
* Convergent synthesis is encountered in
dendrimer synthesis where branches (with the number of generations preset) are connected to the central core.
* Proteins of up to 300
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s are produced by a convergent approach using
chemical ligation
Chemical ligation is a set of techniques used for creating long peptide or protein chains. It is the second step of a convergent approach. First, smaller peptides containing 30-50 amino acids are prepared by conventional chemical peptide synthe ...
.
* An example of its use in
total synthesis is the final step (
photochemical +2 ycloaddition) towards the compound ''biyouyanagin A'':
[''Total Synthesis and Revised Structure of Biyouyanagin A'' ]K. C. Nicolaou
Kyriacos Costa Nicolaou ( el, Κυριάκος Κ. Νικολάου; born July 5, 1946) is a Cypriot-American chemist known for his research in the area of natural products total synthesis. He is currently Harry C. and Olga K. Wiess Professor of ...
, David Sarlah, and David M. Shaw Angew. Chem. Int. Ed.
''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-lengt ...
2007, 46, 4708–4711
:
See also
*
Divergent synthesis In chemistry a divergent synthesis is a strategy with the aim to improve the efficiency of chemical synthesis. It is often an alternative to convergent synthesis or linear synthesis.
In one strategy divergent synthesis aims to generate a library ...
References
Chemical synthesis
{{chemical synthesis