Search results
Results From The WOW.Com Content Network
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.
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.
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.
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]
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.
An example of modest stereoselectivity is the dehydrohalogenation of 2-iodobutane which yields 60% trans-2-butene and 20% cis-2-butene. [5] Since alkene geometric isomers are also classified as diastereomers, this reaction would also be called diastereoselective.
In stereochemistry, an asymmetric carbon is a carbon atom that is bonded to four different types of atoms or groups of atoms. [1] [2] The four atoms and/or groups attached to the carbon atom can be arranged in space in two different ways that are mirror images of each other, and which lead to so-called left-handed and right-handed versions (stereoisomers) of the same molecule.