For question relating to isomers which cause plane polarized light to be rotated in opposite directions.

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Is rotation of a mirror image allowed in order to determine chirality? Doesn't rotation alter the mirror image of the molecule?

So, chiral molecules are those which have non-superposable mirror images. trans-1,2-Dimethylcyclopentane is chiral; 2-butanol is chiral; both don't superpose on their mirror image. Then my book ...
4
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1answer
170 views

How to determine optical activity of a compound without asymmetric carbons theoretically? [closed]

I know that a compound doesn't need to have a chiral carbon to be optically active. So how can I find out whether a compound drawn on paper is chiral without access to any experiments? e.g. ...
10
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1answer
125 views

Taste of sugars' unnatural enantiomers

I'm wondering about how L-sugars taste. They are obviously not digestible by humans, but what do they taste like? If they are sweet, too, why isn't sucrose with the unnatural chirality used as a ...
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1answer
97 views

(Effective) number of molecules interacting with light to produce optical activity

The question is: How can I get a sensible and concrete (not relative) value for the number of molecules light has interacted with to cause an optical activity phenomenon? Specifically, my issue in ...
1
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1answer
41 views

Separating Enantiomers

I understand that you can react enantiomers with a chiral molecule to resolve the enantiomers of interest into diastereomers. However I do not understand how exactly the added chiral molecule can ...
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0answers
27 views

Chirality Centers of Albuterol-like Compounds

My question is apart from the C in the straight chain with $\ce{-OH}$ group, should $\ce{N}$ be counted as chirality center since it also has tetrahedral geometry and all different substituents? ...
2
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1answer
152 views

What kind of optical activity requires chirality?

From "Meso compound" in Wikipedia: A meso compound or meso isomer is a non-optically active member of a set of stereoisomers, at least two of which are optically active. This means that ...
3
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0answers
54 views

What symmetry elements mustn't a molecule possess to be considered achiral?

Undergraduate textbooks say that a molecule mustn't posses a reflection plane and an inversion center to be considered achiral. As mentioned by Ron in his answer to this question, molecules that don't ...
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0answers
28 views

How to interpret the rate constants of in-vivo racemization of thalidomide?

The article by Eriksson et. al. found that thalidomide undergoes chiral inversion in vivo. It found the mean rate constants too, $0.17~\mathrm{h^{-1}}$ (R to S) and $0.12~\mathrm{h^{-1}}$ (S to R). ...
3
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1answer
45 views

How can it be proved that (S)-bis-[2-(t-butylsulfinyl)phenyl] diselenide is a chiral non-racemic product?

I read in paper that: The aim of this part of the work was to synthesise new aromatic diselenides with chiral phosphorous or sulfoxide centres in coordinative distance to the selenium as ...
4
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2answers
77 views

How to determine the number of stereoisomers of a di-substituted allene, exhibiting both axial and central chirality?

What are the diastereomers and enantiomeric pairs of the compound below where A are chiral groups (central chirality)? There should be 3 diastereomers and 3 enantiomeric pairs (last page). I ...
5
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1answer
139 views

How to find the number of stereoisomers of a tetra-substituted allenes, exhibiting both axial and central chirality?

I need a reliable method for determining the number of diastereomers and enantiomeric pairs of the following series of compounds bearing in mind that the substituent groups A are chiral on their own ...
5
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2answers
243 views

Axial or planar chirality in spiro[3.3]hepta-1,5-diene

The two spirocyclic compounds drawn below are enantiomers. My question is, do they exhibit axial or planar chirality? 3D representations:
6
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2answers
112 views

Do more double bonds cause a bigger number of stereoisomers in cycloalkenes?

If trans double bonds cause cycloalkenes to be chiral, does a second trans or maybe cis double bond induce another chiral plane and hence four stereoisomers are possible for the given cyclodiene? The ...
9
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2answers
280 views

Are all higher cycloalkenes chiral?

Are all higher trans-cycloalkenes chiral as trans-cyclooctene is? This question supplements my previous question: Why is trans-cyclooctene chiral? See also the follow-on question: Do more double ...
7
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2answers
286 views

IUPAC name for 1,2,3-trichlorocyclopropane?

What is the IUPAC name for the two isomers of 1,2,3-trichlorocyclopropane? Similarly what is the name for isomers of 1,2,3,4-tetrachlorocyclobutane, 1,2,3,4,5-pentachlorocyclopentane, etc? ...
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1answer
502 views

Why is trans-cyclooctene chiral?

How does trans-cyclooctene exhibit chirality if there are no stereocenters? Related follow-on questions: Are all higher cycloalkenes chiral? Do more double bonds cause a bigger number of ...
6
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1answer
168 views

R-S configuration considering stereoisomerism

How do I consider R-S configuration of this compound? On both the sides of carbon, the groups are same. They differ only in the relative position of hydrogen atoms. On what basis do I assign ...
3
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1answer
82 views

Determining chirality after considering conformational interconversion in a cyclohexane

Basically I want to know what does the question mean when it says "taking into consideration conformational interconversions." I assume it means, when I draw the mirror image of the given compound, ...
3
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1answer
201 views

Defining enantiomer of morphine by R/S designation

How to know if the following chemical structure of morphine is an R or S? What I basically need to know is: which chirality center do we use to make the decision? $\hskip2in$
4
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1answer
100 views

Why is 2-chloropropene achiral?

Could someone explain to me why some alkenes containing at least one couple of different substituents at the two double-bonded C atoms (that is, some of those with at least two different substituents ...
5
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1answer
163 views

Can molten sugar also rotate polarized light as sugar water does?

It is well know that the sugar water can rotate the plane of linearly polarized light, so light bends when travelling in sugar water. However, do the liquid state of sugar but not the sugar solution ...
11
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1answer
324 views

Maximum observed optical rotation through a polarimeter

Is there a maximum optical rotation of plane polarized light that can be observed using a polarimeter? I understand that in a polarimeter, light passes through a filter that converts it into plane ...
3
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1answer
68 views

State of a Racemic Mixture

Is a racemic mixture always an equi-molar solution of two enantiomers, both in the same state? Is it necessary for both isomers to be in the liquid state for racemisation to occur, or does ...
14
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3answers
404 views

How to assign E/Z configuration according to the Cahn-Ingold-Prelog rules when subsituents differ only by stereochemistry

I stumbled-upon this compound: CC=C1C(C)CCC1(C) I'm wondering how to determine the configuration of the double bond. Is it E or Z? How do I decide on the ...
2
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1answer
116 views

Configurations of Reactants in Second Order Nucleophilic Substitutions

The question asks me to draw the product for the reactions. However, I am stuck and do not understand how to draw the reactants with configurations correctly. (a) (S)-2-Chloropentane and NaSH I ...
2
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3answers
281 views

Identifying chiral centers

The compound below is fexofenadine and the only chirality center, as identified by the textbook is, the one circled in red. I do not understand why the carbon attached to the O by a double bond and ...
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4answers
1k views

How to identify a compound as chiral or achiral

I read my book and learned everything about enantiomers, racemization, $\mathrm{S_N1}$ and $\mathrm{S_N2}$ reactions, but when I'm trying to identify molecules as chiral or achiral, I get confused. ...
4
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1answer
108 views

Stereochemistry: R and S notation

How do we number the carbon atoms in symmetrical molecules while giving R and S notation. For instance, in 2,3-Dibromobutane, there is an ambiguity over which is carbon C2 and carbon C3. Will we call ...
2
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1answer
33 views

Chirality, physical or chemical property

Heyo, I was wondering whether one would consider chirality a physical or chemical property. In my opinion it should be both, because it will affect the way in which plane polarized light is interacted ...
2
votes
1answer
87 views

Can pseudochirality be considered when 3 or 4 groups on the C atom are the same?

When for example the C atom is bonded to one H, and then three more structurally identical groups with 2 chiral C each - in configurations R,R and S,S and R,S respectively - then by assigning each of ...
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0answers
71 views

Chirality vs Resonance in chemical structure

In a reference book, chirality of a molecule is explained as "handedness", like our right and left hand, which are mirror images of each other. These are also called as enantiomers. The nearest clue ...
2
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2answers
489 views

Chirality on Propranolol

I'm a bit confused when asked to specify the chiral carbons on this sketch of Propranolol as I'm not sure how the $\ce{H3C}$ and $\ce{CH3}$ play in if they are reversed in the name like that...Does ...
2
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2answers
40 views

Is there anything akin to molecular chirality for crystalline?

For example, in hexagonal closed-packed (HCP) structure, the atoms may be arranged in ABAB stacks or ACAC stacks. Can these two be considered enantiomers? Do they possess different solid state ...
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2answers
3k views

Are all amino acids except glycine chiral compounds?

Specifically, I was thinking of the case where the R group is a carboxylic acid functional group or an amine group. Then there would not be a chiral carbon atom. Is there a restriction on what can be ...
3
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1answer
91 views

Is bicyclo[1.1.0]butane chiral?

Is bicyclo[1.1.0]butane chiral? I think it isn't, but if one of the hydrogen atoms bound to the tertiary or secondary carbon atoms is replaced with e.g. chlorine, the formed compound will be chiral, ...
2
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4answers
110 views

Gas phase chiral molecules

Are there any molecules that are chiral that are also gases at room temperature? Failing that, what chiral molecules have a high vapor pressure? Propylene oxide has a boiling point of only 34 C, so ...
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3answers
583 views

How can I determine the number of possible pairs of diastereomers?

How can I determine the number of possible pairs of diastereomers here? Here was the question: "How many pairs of diastereomers are possible in the following molecule? PhCH(Cl)CH(Ph)CH(Cl)Ph" I ...
3
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3answers
2k views

Concept of “non-superimposable mirror image” in chirality

I didn't understand the fact that chiral objects are non-superimposable on their mirror images. I mean, if you put your right hand (apparently an achiral object) in front of a mirror, the mirror image ...
0
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1answer
149 views

What are some of the simplest chiral molecules in biological systems

I have understood generally for a while there is a significant preference in "life" for so-called "left-handed" (chiral) molecules, though I'm reading things now that say "life" sugars are ...
2
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1answer
120 views

Are Grignards Chiral?

Can Grignards be chiral? I've seen them drawn as ionic structures in class. I've also seen little asterisks on certain positions of Grignards (a common designation of chirality). So this begs the ...
3
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1answer
370 views

Assign the configurations of the stereo centres in (-)-menthol and (+)-neomenthol?

I have to assign R or S to the chiral centers in (-)-menthol and (+)-neomenthol. The results I got are shown below in the picture. However, when I looked on Wikipedia to check my answers they ...
3
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1answer
228 views

Simple experiments involving enantiomer synthesis

I want to do an experiment to investigate factors affecting the synthesis of chiral molecules. The only problem is, my institution doesn't have much money, and it seems like the chemicals required for ...
6
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1answer
1k views

What are chiral environments?

I keep seeing the term cropping up, but cannot seem to find a definition for it. My understanding is that it is an environment in which, when the isomers interact with the environment, the two ...
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2answers
165 views

Chirality of heteroatoms

Why is a phosphorus atom with three different substituents chiral, but nitrogen isn't? Nitrogen inverts fast, while phosphorus obviously much slower. How is that explained?
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2answers
340 views

Isopropyl and Butyl Groups - Relative Priorities

This does not compute for me: Why would the four-carbon butyl group have a lower relative priority than the 3 carbon isopropyl group? If we compare the carbons one by one between the isopropyl and ...
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1answer
144 views

How to Rotate Chiral Carbon

I know that to correctly assign R,S priorities I have to rotate the above figure until the H is projecting into the page (away from me). However, I don't know how to rotate the H and the rest of the ...
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2answers
48 views

Does the Arrangement of Atoms Matter Around Chiral Carbon?

In other words, are these two structures equivalent?
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1answer
24 views

Configuration, chirality

I'm having trouble assigning priorities for this molecule: I tried assigning priorities with the rules for doubly bonded atoms in mind. I know that the lowest priority group should be going into the ...
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1answer
642 views

Drawing (R)-1,1,2-trimethylcyclohexane

I tried drawing out (R)-1,1,2-trimethylcyclohexane but I can't seem to figure it out. I think I"m getting hung on assigning priorities. I've labeled the chiral carbon with an asterisk. I've also ...