Chiral pool synthesis
Encyclopedia
Chiral pool synthesis is a strategy that aims to improve the efficiency of chiral synthesis
. It starts the organic synthesis
of a complex enantiopure chemical compound
from a stock of readily available enantiopure substances. Common chiral starting materials include monosaccharide
s and amino acid
s. The built-in chirality
is then preserved in the remainder of the reaction sequence.
This strategy is especially helpful if the desired molecule bears a great resemblance to cheap enantiopure natural products. Otherwise, a long, tortuous synthesis involving many steps with attendant losses in yield may be required. At times, it may be difficult to find a suitable enantiopure starting material; other techniques may prove more fruitful.
General methods used in chiral pool synthesis are the use of protecting groups, and functional group interconversion (FGI).
molecule (an alternative to Paclitaxel
), from readily available enantiopure (–)-pantolactone. Enantiopure tartaric acid
is also used to synthesize chiraphos
:
s is synthesized from which a diverse family of molecules can be constructed .
Chiral synthesis
Enantioselective synthesis, also called chiral synthesis, asymmetric synthesis or stereoselective synthesis, is organic synthesis that introduces one or more new and desired elements of chirality...
. It starts the organic synthesis
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
of a complex enantiopure chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
from a stock of readily available enantiopure substances. Common chiral starting materials include monosaccharide
Monosaccharide
Monosaccharides are the most basic units of biologically important carbohydrates. They are the simplest form of sugar and are usually colorless, water-soluble, crystalline solids. Some monosaccharides have a sweet taste. Examples of monosaccharides include glucose , fructose , galactose, xylose...
s and amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s. The built-in chirality
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....
is then preserved in the remainder of the reaction sequence.
This strategy is especially helpful if the desired molecule bears a great resemblance to cheap enantiopure natural products. Otherwise, a long, tortuous synthesis involving many steps with attendant losses in yield may be required. At times, it may be difficult to find a suitable enantiopure starting material; other techniques may prove more fruitful.
General methods used in chiral pool synthesis are the use of protecting groups, and functional group interconversion (FGI).
Examples
Chiral pool synthesis is used to build a part of the epothiloneEpothilone
The epothilones are a new class of cancer drugs. Like taxanes, they prevent cancer cells from dividing by interfering with tubulin, but in early trials epithilones have better efficacy and milder adverse effects than taxanes....
molecule (an alternative to Paclitaxel
Paclitaxel
Paclitaxel is a mitotic inhibitor used in cancer chemotherapy. It was discovered in a U.S. National Cancer Institute program at the Research Triangle Institute in 1967 when Monroe E. Wall and Mansukh C. Wani isolated it from the bark of the Pacific yew tree, Taxus brevifolia and named it taxol...
), from readily available enantiopure (–)-pantolactone. Enantiopure tartaric acid
Tartaric acid
Tartaric acid is a white crystalline diprotic organic acid. It occurs naturally in many plants, particularly grapes, bananas, and tamarinds; is commonly combined with baking soda to function as a leavening agent in recipes, and is one of the main acids found in wine. It is added to other foods to...
is also used to synthesize chiraphos
Chiraphos
Chiraphos is a chiral diphosphine employed as a ligand in organometallic chemistry. This bidentate ligand chelates metals via the two phosphine groups. Its name is derived from its description — being both chiral and a phosphine...
:
Enantiomeric scaffolding
Enantiomeric scaffolding is a related concept whereby a conceptually simple but synthetic core molecule of high enantiopurity with many functional groupFunctional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
s is synthesized from which a diverse family of molecules can be constructed .