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Very often, cis–trans stereoisomers contain double bonds or ring structures. In both cases the rotation of bonds is restricted or prevented. [4] When the substituent groups are oriented in the same direction, the diastereomer is referred to as cis, whereas when the substituents are oriented in opposing directions, the diastereomer is referred to as trans.
1,2-Diaminocyclohexane (DACH) is an organic compound with the formula (CH 2) 4 (CHNH 2) 2. It is a mixture of three stereoisomers: cis-1,2-diaminocyclohexane and both enantiomers of trans-1,2-diaminocyclohexane. The mixture is a colorless, corrosive liquid, although older samples can appear yellow. It is often called DCH-99 and also DACH.
trans-1,2-Diaminocyclohexane is an organic compound with the formula C 6 H 10 (NH 2) 2. This diamine is a building block for C 2-symmetric ligands that are useful in asymmetric catalysis. [1] A mixture of all three stereoisomers of 1,2-diaminocyclohexane is produced by the hydrogenation of o-phenylenediamine.
Stereochemistry, a subdiscipline of chemistry, studies the spatial arrangement of atoms that form the structure of molecules and their manipulation. [1] The study of stereochemistry focuses on the relationships between stereoisomers, which are defined as having the same molecular formula and sequence of bonded atoms (constitution) but differing in the geometric positioning of the atoms in space.
For example, dibromocarbene and cis-2-butene yield cis-2,3-dimethyl-1,1-dibromocyclopropane, whereas the trans isomer exclusively yields the trans cyclopropane. [ 4 ] This addition remains stereospecific even if the starting alkene is not isomerically pure, as the products' stereochemistry will match the reactants'.
Le Bel-van't Hoff rule states that for a structure with n asymmetric carbon atoms, there is a maximum of 2 n different stereoisomers possible. As an example, D-glucose is an aldohexose and has the formula C 6 H 12 O 6. Four of its six carbon atoms are stereogenic, which means D-glucose is one of 2 4 =16 possible stereoisomers. [20] [21]
In chemistry, stereoselectivity [1] is the property of a chemical reaction in which a single reactant forms an unequal mixture of stereoisomers during a non-stereospecific creation of a new stereocenter or during a non-stereospecific transformation of a pre-existing one. [2]
For example, 2-butene exists in two isomeric forms: cis-2-butene and trans-2-butene. [2] The sub-categories of isomerases containing racemases, epimerases and cis-trans isomers are examples of enzymes catalyzing the interconversion of stereoisomers.