Questions tagged [chirality]
Applicable to questions about the ability of a molecule (or class of molecules) to be superimposed on their mirror image(s).
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Which enantiomer of 3-Chloro-2-pentanol is this?
I think that there is a chiral centers at $C_2$ and at $C_3$ (Numbering starting such that the carbon with hydroxy attached is number 2.
Then, for $C_2$:
Priority would be: OH > $C_3$ > $C_1$ &...
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Why the C4 in this 1,3,4,5-substituted Cyclohexanes has a R/S configuration?
(1S,3S,4S,5S)-3,5-dimethoxy-1-phenylcyclohexane-1,4-dithiol.
ChemDraw21 shows the C4 is S configuration. However I think C4 has two same function groups(C3 and C5 are both S configuration; C2-1-6 and ...
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Doubt in chirality and pseudo chirality
So a carbon atom is chiral if it has 4 different group attached to it, and it is pseudo chiral if it has 3 different groups of atoms attached to it, where the 2 similar groups have different ...
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To what extent should a question such as: "how many enantiomers are there?" take geometric isomerism into account?
Pretty simple question here.
How many enantiomers are there for the structure $\ce{CH3CH=CHCH(CH3)CH2CH3}$?
On the one hand, there is just one chiral centre so one would suggest $2$. On the other ...
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Why is Carbon marked as 1 acting like a pseudo chiral centre?
Since there is a plane of symmetry passing through the middle of the compound, the C (chiral centres) at 2 and 3 will rotate the light through angles opposite in magnitude, say, +A and -A respectively ...
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Why are carbon atoms of glucose considered chiral?
A chiral carbon atom is defined as
"a carbon atom with four different groups attached to it."
I am aware that the open-chain form of glucose has four chiral carbon atoms.
However, I do ...
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Are meso compounds also included in optical isomers or are they just stereoisomers
Our teacher has taught us today about optical isomers . And at the end given a formula for finding number of optical isomers of a symmetrical molecule( n is number of chiral atoms and the n is odd for ...
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Assigning configuration of chiral plane - selecting of the pilot atom
I am little confused about when it comes to assigning configuration of planarly chiral cyclophanes - and I think it comes down to selection of pilot atom.
All sources I have came across say that the ...
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Can we always use the planar representation of cycloalkanes instead of their true conformations to study their stereochemistry and chirality?
When I have drawn stereoisomers of substituted cyclohexanes and checked if they are chiral, I typically represent the ring as a planar hexagon and look for symmetry elements. For example, I would use ...
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Which one has higher priority in CIP rules -- O or OH?
I know that if the atom is the same, I have to look at the next atom. In the first choice, Oxygen is not connected to any other atom (besides the chiral carbon). It is an anion. Whereas in the second ...
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Does norcamphor have enantiomers?
The following two molecular structures have two chiral centers, so in total four chiral centers:
I did the absolute configuration multiple times and I keep getting R,R and S,S, which should be ...
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How can a molecule with a double bond on one side have a plane of symmetry, and thus, be achiral?
Does norbornene have a plane of symmetry? Is norbornene achiral or chiral?
I think norbornene is chiral since there is a double bond on the only one side. Thus, there is no plane of symmetry. The ...
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Why does 2,3 dichlorobutane have 2, and not 3, stereoisomers
I understand how and that the R,S and R,R stereoisomers are different.
But I don’t see why the R,R and S,S compounds are stereoisomers and not meso compounds with each other.
Online it says that ...
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Is There a Problem with the Assignment of Stereochemical Descriptors by ChemDraw in Select Examples?
While using ChemDraw Professional 21.0.0.28 to construct some cyclic allenes and rotationally restricted biphenyls, I came across anomalous assignments of stereochemistry. [For the latest version of ...
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Why this structure is diastereomers instead of enantiomers
In this diagram optical isomers has divided in to 2 categories, one is diastereomers and enantiomers. Is the example for diastereomers correct? For me its looks like enantiomers
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Of 2-bromobutan-2-ol and trans-1,2-dimethylcyclobutane which is chiral as well as dissymmetric?
In an examination I was asked to determine the molecules which are chiral as well as dissymmetric. There were four options, and among them, two were achiral, as they had an improper axis of symmetry. ...
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Chirality of conformations of butane
I have read that the conformations of butane are as follows:
I came across a question about number of chiral conformations of butane.
My Attempt :
The total or fully eclipsed is achiral because it ...
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Confusion in R/S Nomenclature and Chirality [closed]
I have many confusions regarding optical isomerism:
What is the use of the R/S nomenclature? I understand that it is used to distinguish between the different spacial arrangements that are possible ...
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How many stereogenic centers exist in the atropine?
I'm pretty sure that both C bonded to N are stereogenic centers. I don't know about the others, any help? Is this correct?
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Does 1,4-dimethylcyclohexane have a chiral center?
My textbook says that 1,4-dimethylcyclohexane (cis or trans) does not have a chiral centre, since two groups on the tertiary carbon (that are the part of the ring) are identical, and thus the compound ...
user92687
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Are all chiral carbons sp3 hybridised? [closed]
I had this doubt, whether all asymmetric chiral carbons must necessarily be $\mathrm{sp^3}$ hybridized. For sure, we know that double or triple bonded carbon atoms don't shows such chirality, but is ...
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Why does an improper rotation axis preclude chirality?
Can anybody prove that any molecule with an axis of improper rotation is nonchiral? I still do not understand why this is so, any proper mathematical proof or visualisation of a generalised molecule ...
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Why do Enantiomers have different chemical properties with optically active reagents?
As I understand Enantiomers have similiar physical properties but they do show different chemical properties with optically active reagents. This point is something which I am not able to logically ...
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Can bromo(chloro)fluoro(iodo)methane be synthesized? [closed]
Bromo(chloro)fluoro(iodo)methane is supposed to have all of the stable halogens a part of this molecule: fluorine, chlorine, bromine, and iodine. Can it really able to be synthesized and if so could ...
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How can a compound having a plane of symmetry be Chiral?
The compound( Given in the image below) is treated with $\ce{excess H2 in Pt}$.
Here, (a) - The given compound. (b) - What the answer should be according to me.
(c) - What the actual answer is:
Q1 - ...
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Does the 3D conformation of rings affect chirality?
During the chirality analysis of various molecules containing rings, we assume for convenience that the rings are completely flat/planar and if the molecule has a plane of symmetry, it is achiral. ...
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What exactly is a 'chiral centre' in a carbon compound? [duplicate]
The typical progression (in books, YouTube videos) of explanation of chiral carbons in a compound is as follows:
Chiral compounds are non-superimposable by their mirror-image;
It is easily seen that ...
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In a pair of diastereomers, which of the following is true?
While going through my book, I came across this question and got really confused. Here's what the problem was:
In a pair of diastereomers,
Both can be laevo-rotatory or both can be dextro-rotatory
...
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Does the chlorination of 4-methylcyclopentene generate two enantiomers or two diastereomers?
Does the chlorination of 4-methylcyclopentene generate two enantiomers or two diastereomers?
I think it makes two enantiomers (or one pair of enantiomer) since the starting compound is achiral, but ...
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Is 2 ethyl 3 methyl oxirane optically active?
According to me this molecule does not have any any plane of symmetry nor centre of symmetry, but in my textbook it is given that this is optically inactive.
user102573
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Why is ephedrine optically active? [closed]
Acyclic amine in which three groups are different with a lone pair of electron is optically inactive and nitrogen is achiral because of the rapid pyramidal inversion.
Does similar inversion happen in ...
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How is the central carbon in 3‐bromopentane‐2,4‐diol chiral?
My teacher told us the middle carbon in 3‐bromopentane‐2,4‐diol is chiral:
$$\ce{CH3-CH(OH)-\overset{\star}{C}H(Br)-CH(OH)-CH3}$$
Since there are two identical groups around it, I would guess it ...
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What are the criteria for a molecule to be chiral?
What are the criteria for a molecule to be chiral?
(We frequently get questions of this type, so this is an attempt to construct a suitable general answer for duping.)
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Chirality and Optical activity
Do all chiral objects rotate the plane of polarization of EM waves? For example my hand is chiral, will it rotate the plane of polarization of EM waves of suitable wavelength?
user102687
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Is (1R,3aR,4S,6aS)‐1,4‐dibromo‐octahydropentalene chiral or achiral?
Is this molecule on the left chiral or achiral?
I believe it is achiral because its mirror image (on the right) is essentially the same molecule. But I was told that it is chiral because it doesn't ...
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Are all 'dextrorotatory' sugars in biology actually 'd' or '+' in chirality?
When papers or articles say that all proteinogenic amino acids are 'levorotatory' or 'L', they often make a point of saying that only half of them are truly, optically levorotatory. All of them (...
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Why is 1-Ethyl-1-methylcyclohexane achiral? [closed]
I was wondering why the 1-Ethyl-1-methylcyclohexane molecule is achiral.
Thank you in advance.
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How come the C1 is above the ring in fructose-6-phosphate and C1 is below the ring in fructose-1,6-bisphosphate?
Does the phosphofructokinase-1 flip the position of the covalent bonds? If I've understood correctly, C2 is a chiral atom, so it would make a difference if C1 goes from above the C2 to below the C2.
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In which of the these structures C-3 carbon is not a chiral centre?
In which of the these structures C-3 carbon is not a chiral centre?
I think that the answer to the above question should be both (b) and (c) as C-3 is attached to same groups and also they have a ...
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Example of an achiral molecule without a plane of symmetry or inversion center?
Some websites, such as this textbook, mention how generally a plane of symmetry or inversion center in a molecule is enough to consider it achiral. Nonetheless, this source clarifies
but if these ...
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Why does [Ni(gly)2] show optical isomerism despite having no chiral carbon?
For optical isomerism chiral carbon should be present i.e. carbon with four different groups but this compound doesn't have one then why does it show optical isomerism?
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Is plane of symmetry a necessary and sufficient condition for optical inactivity in coordination compounds? [closed]
In organic chemistry, we have to check for all three types of symmetry in a compound to check its chirality, ie, plane, alternate axis and centre of symmetry. But in coordination compounds, do we need ...
user92687
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Do we need to check for all kinds of symmetry in a compound to declare it achiral?
I know that a compound is achiral if it contains any one of the following kind of symmetry.
1.Plane of symmetry
2.Centre of symmetry
3.Normal axis of symmetry
4.Alternate axis of symmetry
It is ...
user92687
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Type of chirality in polycyclic compounds
Ignoring whether or not this molecule could exist, is there a name for this type of chirality? This molecule's mirror image cannot be superimposed on itself but there are no chiral centres.
Even ...
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Why can't an "upside down" chiral molecule neutralize the polarized light effect? [duplicate]
Steve Mould did a nice video a few months back called "Why Sugar Always Twists Light To The Right" (link is timestamped at the critical part).
However his explanation was not complete.
He ...
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Why has this molecule a S-chirality? [closed]
Can someone explain to me, why this molecule has an (S)-chirality? I don't get it. I tried to apply the rules, but I get only an (R)-chirality. Is there something special with cyclo-alkanes?
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Number of chiral centers in penicillin V
I have often seen that in many drugs chirality plays a role. So I was trying to analyze the structure of Penicillin V.
What is number of chiral centers in the structure of penicillin V? Is the ...
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Which chiral carbon do L and D in L- or D-glucose refer to? [duplicate]
I see and D- and L- glucose are mirror images of each other. and I understand D and L are for chirality. But it is not clear which carbon do D and L refer to. Could anybody let me know? Thanks.
What ...
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Do different alkyl groups affect chirality?
I am a bit confused on the definition of a chiral center;
A carbon atom is chiral if it has four different items bonded to it at the same time. source
However I am not sure whether different alkyl ...
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