What is Re and Si face?
A face is labeled re if, when looking at that face, the substituents at the trigonal atom are arranged in increasing Cahn-Ingold-Prelog priority order (1 to 2 to 3) in a clockwise order, and si if the priorities increase in anti-clockwise order; note that the designation of the resulting chiral center as S or R depends …
What is S and R configuration?
If the three groups projecting toward you are ordered from highest priority (#1) to lowest priority (#3) clockwise, then the configuration is “R”. If the three groups projecting toward you are ordered from highest priority (#1) to lowest priority (#3) counterclockwise, then the configuration is “S”.
What is prochirality explain with example?
An achiral object which is capable of becoming chiral in two desymmetrisation steps is sometimes described as proprochiral. For example the proprochiral CH3CO2H becomes prochiral as CH2DCO2H and chiral as CHDTCO2H. 2.
What is R or S in chemistry?
A counterclockwise direction is an S (sinister, Latin for left) configuration. A clockwise direction is an R (rectus, Latin for right) configuration.
What does Enantiotopic mean?
Enantiotopic. The stereochemical term enantiotopic refers to the relationship between two groups in a molecule which, if one or the other were replaced, would generate a chiral compound. The two possible compounds resulting from that replacement would be enantiomers.
How do you write R and S configuration?
Draw an arrow starting from priority one and going to priority two and then to priority 3: If the arrow goes clockwise, like in this case, the absolute configuration is R. As opposed to this, if the arrow goes counterclockwise then the absolute configuration is S.
How do you name R and S stereoisomers?
If it is going clockwise, then it is an R-enantiomer; If it is going counterclockwise, it is an S-enantiomer.
What are pro R and Pro S?
Enantiotopic or diastereotopic pair of atoms or groups on a prochiral centre in a molecule is designated as pro-R and pro-S if replacement of one of them by an achiral ligand with higher priority than the other in the sense of CIP rule, without disturbing the priority of remaining ligands, convert the prochiral centre …
What is R & S isomer?
The R and S isomers are organic molecules having a chiral center, which is a carbon atom that has four different substituents attached to it. These substituents get listed according to their priority (the priority is determined using CIP rules as described below).
What is regioselectivity and stereoselectivity?
Regioselectivity concerns what region of the molecule reacts to form selective products. Many addition reaction have this kind of selectivity. Stereoselectivity concerns in what conformation the products will be after a reaction.
What is stereospecific and non stereospecific?
A stereospecific mechanism specifies the stereochemical outcome of a given reactant, whereas a stereoselective reaction selects products from those made available by the same, non-specific mechanism acting on a given reactant.
How to determine whether the face of the attached alkene is re/si?
How to determine whether the face of the attached alkene is re or si? If assigning priorities in regard to the left C atom it is re, but for the right C atom it is si. How is it actually determined? Show activity on this post.
What are the rules of Nomenclature for alkenes?
The rules for alkenes are similar to those used for alkanes. The following rules summarize alkene nomenclature. 1. Identify the longest continuous chain of carbon atoms that contains the carbon‐carbon double bond.
What is the IUPAC name for alkene?
draw the Kekulé, condensed or shorthand structure of an alkene (cyclic or acyclic), given its IUPAC name. give the IUPAC equivalent of the following trivial names: ethylene, propylene, isobutylene and isoprene. draw the structure of a vinyl (ethenyl) and allyl (2-propenyl) group, and use these names in alkene nomenclature.
How do you find the double bond number of an alkene?
The position of the double bond is indicated by placing the lower of the pair of numbers assigned to the double‐bonded carbon atoms in front of the name of the alkene. Thus, the compound shown in rule 2 is 2‐pentene.