Search results
Results from the WOW.Com Content Network
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.
E–Z configuration, or the E–Z convention, is the IUPAC preferred method of describing the absolute stereochemistry of double bonds in organic chemistry. It is an extension of cis – trans isomer notation (which only describes relative stereochemistry ) that can be used to describe double bonds having two, three or four substituents .
The descriptors cis (Latin, on this side of) [2] and trans (Latin, over, beyond) [3] are used in various contexts for the description of chemical configurations: [4] [5] In organic structural chemistry , the configuration of a double bond can be described with cis and trans , in case it has a simple substitution pattern with only two residues.
The molecular configuration of a molecule is the permanent geometry that results from the spatial arrangement of its bonds. [1] The ability of the same set of atoms to form two or more molecules with different configurations is stereoisomerism. This is distinct from constitutional isomerism which arises from atoms being connected in a different ...
The relative importance of the cis and trans influences depends on the formal electron configuration of the metal center, and explanations have been proposed based on the involvement of the atomic orbitals. [8] Example of the structural trans effect: the effect induced by triethylphosphine ligands is stronger than induced by chloride ion ligands.
For instance, it can be prepared in almost 100% yield by converting the cis isomer to 1,2-epoxycyclooctane ("cyclooctene oxide") followed by reactions with lithium diphenylphosphide (LiPPh 2) and with methyl iodide CH 3 I. (Similar procedures can give cis,trans isomers of 1,4-cyclooctadiene and 1,5-cyclooctadiene). [2]
On the other hand, cis-4-tert-butylcyclohexyl chloride undergoes elimination because antiperiplanarity of Cl and H can be achieved when the t-Bu group is in the favorable equatorial position. Thermodynamically unfavored conformation of trans -4- tert -butylcyclohexyl chloride where the t -Bu group is in the axial position exerting 7-atom ...
In chemistry, absolute configuration refers to the spatial arrangement of atoms within a molecular entity (or group) that is chiral, and its resultant stereochemical description. [1] Absolute configuration is typically relevant in organic molecules where carbon is bonded to four different substituents .