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Applicable to questions about the spatial arrangement of atoms in a molecule and how they affect its physical or chemical properties.

-1
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1answer
28 views

Stereochemistry of cyclic alkane [on hold]

Why are the following compounds diastereomers ?
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0answers
28 views

Stereochemistry [on hold]

The answer to this question is option (d). Can anyone please explain the reason?
2
votes
1answer
96 views
-1
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0answers
12 views

Clarification regarding pure chiral isomers [closed]

I was doing some stereochemistry and i got a confusion about the exact definition of pure chiral isomers.Isnit possible that pure chiral reagent can only have one stereogenic center?thanks for help ...
2
votes
2answers
76 views

Can chiral atoms have same substituents but with different orientations?

So consider this molecule. We have to determine whether nitrogen atom is chiral or not. MY IDEAS: Now going by all I have read, for chiral atoms only criteria is substituents to be different. Here ...
-1
votes
0answers
22 views

Number of Geometrical isomer [closed]

Number of geometrical isomers in the molecule
9
votes
5answers
835 views

If a chiral molecule reacts with an achiral molecule will the product be chiral or achiral?

My book says that a pair of enantiomers will react the same way with an achiral substance. How is this possible? Does this imply that the product is achiral, even though the enantiomers are chiral? ...
2
votes
1answer
46 views

Number of spatial arrangements of tetrasubstituted biphenyl?

According to my book 2-bromo-2'-(1-chloroethyl)-6'-iodo-6-(prop-1-en-1-yl)-1,1'-biphenyl has eight possible spatial arrangements. How can this be so? I can think of only four – left two groups being ...
-1
votes
0answers
25 views

Stereochemistry confusion [duplicate]

While dealing with molecules we try rotate the mirror images and then try to superimpose them. That's ok . But our hand are mirror images and I tried a exercise by keeping both hands like this Then ...
1
vote
1answer
43 views

Cahn–Ingold–Prelog priority of CN vs CH2NH2

Why does $\ce{CH2NH2}$ have lower priority than $\ce{CN}$? The carbon on the first molecule is bonded to (N,H,H) while the carbon on the second molecule is just bonded to (N). I can't seem to find ...
0
votes
0answers
33 views

What compounds give two products on reacting with NH2OH?

This is a question from the chapter stereochemistry of my coaching module. The answer options include CH3CHO, DCHO, etc. How do I do this? I have an idea that if we take a racemic mixture of D and L ...
6
votes
2answers
451 views

Do you assume undrawn hydrogens are pointing away from you when determining R/S?

When determining R/S of stereoisomers, the group with the smallest atomic number needs to be in the back (dashed line). But if no group attached to a chiral center is drawn in dashed line, do we ...
-1
votes
1answer
43 views

Twisting stereoisomers with rings to determine R/S [closed]

I know that if the smallest atomic number group is not in the back, we can twist the molecule so that it is in the back and then determine if it is R/S (Left image). But if the chiral center is ...
-1
votes
1answer
38 views

Stereogenic Center Question

In cholesterol, I don't understand why the two points I circled are stereogenic centers. Isn't the left carbon attached to an OH, H, CH2, and CH2? And isn't the right carbon attached to CH, CH2, CH, ...
-1
votes
1answer
81 views

Explain optical activity in Biphenyl compounds

How is optical activity explained in biphenyl compounds using atropisomerism. NOTE: I was taught that if vertical symmetry exists then optical activity is not shown by any substituted biphenyl ...
1
vote
2answers
98 views

H-NMR Equivalent Protons and Coupling of Glycerol

I've been searching for explanations to understand why the labeled protons on carbons 1 and 3 are not equivalent in the below figure. Another figure that shows the same results: SDBS confirms the ...
0
votes
1answer
72 views

Systematic Approach to Finding Number of Isomers [duplicate]

I have this compound I want to know how many isomers (including stereoisomers) may have this constitution. Is there a systematic approach towards solving such types of problems related to the total ...
0
votes
0answers
49 views

How many stereoisomers can exist for 4,5-bis(3-hydroxyoct-1-en-1-yl)cyclopentane-1,3-diol?

This is from this year's JEE Advanced question paper. I thought the answer to be atleast 32 because of exactly 5 stereocentres present. One of the double bond cannot show geometrical isomerism ...
0
votes
2answers
56 views

Meso and achiral does both term means the same?

When a molecule has plane of symmetry, or centre of symmetry it is termed as an achiral compound (though it contain some chiral centres). Same goes for the meso compounds due to the internal ...
2
votes
0answers
54 views

Dextro or laevo-rotatory compound conversion [closed]

Will applying an external electric field to a racemic mixture will convert the optically active compound(mixture of both Dextro and laevo-rotatory) into a particular dextro or laevo-rotatory compound? ...
3
votes
1answer
49 views

Under what circumstances can the stereochemistry at nitrogen atom be faithfully retained and identified?

Under what circumstances can the stereochemistry at nitrogen atom be faithfully retained and identified? Because in most cases nitrogen atoms tend to undergo stereorandomisation by flipping due to ...
0
votes
1answer
57 views

1,4-diphenyl-1,3-butadiene (E,E) and (E,Z) Isomer Newman Projections

I was wondering if it is possible to draw the Newman projections of the (E,E) and (E,Z) isomers of 1,4-diphenyl-1,3-butadiene in the following manner that I have? I wasn't quite sure about how to ...
3
votes
1answer
139 views

How to calculate the percentage yield for enantiomers in free radical halogenation?

How many mono-chlorinated products of 2-methyl butane will be formed upon chlorination in the presence of sunlight? Find the percentage of major product formed. Six products were formed: two ...
-1
votes
1answer
65 views

Number of total stereoisomers of a piperazine derivative

How do I find out the total number of stereoisomers of 3,6-dimethylpiperazine-2,5-dione? As far as I can see, the compound has two chiral carbons. Would the nitrogens make a difference? They seem ...
2
votes
0answers
58 views

Does dihydroimidazole show geometrical isomerism?

Does dihydroimidazole (above) exhibit geometrical isomerism? Does the fact that the lone pair is involved in conjugation with a double bond affect anything? As far as I know, it does not exhibit ...
12
votes
2answers
396 views

Number of stereoisomers of tetramethylspirononane

The above compound – 2,3,7,8-tetramethylspiro[4.4]nonane – clearly exhibits both optical and geometrical isomerism. The question is, how many stereoisomers does it have in all? As the number of ...
2
votes
0answers
84 views

How to find the number of optically active and optically inactive isomers for a spiropentane derivative? [duplicate]

What will be the number of optically active and inactive isomers 1,2,4,5-tetramethylspiro[2.2]pentane? The question asked for the difference between number of optically active and optically inactive ...
0
votes
1answer
44 views

Could thin layer chromatography separate enantiomers? [duplicate]

My textbook states the thin layer chromatography could separate enantiomers only if both/or the mobile and solid phases are chiral? Why so?
0
votes
1answer
93 views

What is the difference between chiral molecule and chiral carbon? [duplicate]

I read in my book, that substituted allenes do not have chiral carbons, but actually the molecule is chiral, so they show optical isomerism. But what is the difference between them( chiral carbon and ...
4
votes
2answers
108 views

Determining the stereochemistry of the product(s) when an alkyl shift in a carbocation generates a chiral carbon

Consider this carbocation: We know that this carbocation would immediately rearrange - by a methyl shift - to form the more stable carbocation. Now, notice that the migration will produce a chiral ...
3
votes
1answer
35 views

Effect of stereoisomerism and racemization on solubility

I was on the Wikipedia page of Tartaric Acid, and I noticed that its solubility in water varies depending on whether the solution is racemic, meso, or optically active: $$\begin{array}{|c|c|} \hline &...
0
votes
1answer
60 views

What is it meant by two different groups in stereoisomerism?

I understand there are some properties in an organic compound that allow stereoisomerism. double bond can't rotate two double bonded carbon atoms each have two different atoms or groups attached I'm ...
4
votes
1answer
52 views

Stereoselectivity of Roush crotylboration

One can use a tartrate derived boronate to enact enantioselective crotyl transfer. Eg in scheme below: I do not understand how the stereoselectivity arises. We have a chiral boronate, true, and we ...
1
vote
0answers
35 views

Can a molecule be achiral whilst it's resonance form chiral? [duplicate]

I'm trying to work out whether this It is my understanding that the sulfur is sp2 hybridised. Why is this? The central sulfur atom is bound to 3 atoms and then has a lone pair, so surely it is sp3 ...
2
votes
1answer
34 views

Is there a characterisation for conjugated dienes similar to cis-trans?

As shown above,we know there are two configurations possible for conjugated dienes. Are they given any special names like we have cis and trans? This came up because while studying the Diels Alder ...
0
votes
1answer
235 views

Which one of the following is optically active?

To be optically active the presence of chiral centres are very important but if there exists a plane centre or axis of symmetry then the molecules are optically inactive. How to determine the optical ...
0
votes
2answers
130 views

Esterification of racemic acid with optically active alcohol

An excess of racemic acid ($\ce{CH3CHClCOOH}$) is allowed to react with (S)-2-methyl-1-butanol to form the ester, $\ce{CH3CHClCOOCH2CH(CH3)CH2CH3}$, and the reaction mixture is carefully distilled. ...
8
votes
4answers
397 views

Mismatch of plane of symmetry vs Gold Book's definition for a pseudochiral carbon

Here is pentane-2,3,4-triol: At first glance, without deciding the configurations at each chiral carbon, we can clearly see that this molecule has a plane of symmetry, perpendicular to the plane of ...
-1
votes
1answer
98 views

Counting number of stereo isomer

I am having trouble counting the stereo-isomers in this structure: There are no chiral carbons. The double bonds means there maybe cis-trans geometrical isomerism but the groups are different. So ...
-3
votes
1answer
312 views

Difference between L&D and S&R in naming [duplicate]

What is the difference between L&D and S&R? Can we say S-alanine instead of L-alanine?
1
vote
1answer
270 views

How are these molecules chiral and achiral?

I always thought that a molecule couldn't be chiral if it had a plane of symmetry. Doesn't the chiral molecule here have symmetry diagonally across the OHs? The achiral one doesn't look symmetrical ...
8
votes
1answer
355 views

Racemization of ketones in presence of catalytic acid

Question: Which of the following ketones racemise in aqueous solution containing acidic or basic impurities? My answer: A and B should racemise in aqueous solution, for the carbonyl groups in A and B ...
3
votes
1answer
107 views

Understanding the CIP configuration for cyclic substituents with hetero-oxygen atoms

As per CIP sequence rules, the topmost $\ce{C}$ on the left gets 1st priority. Moving on to the right side of the double bond, we have: Top $\ce{C}$: ($\ce{C}$,$\ce{O}$,$\ce{O}$,$\ce{H}$) Bottom $\...
13
votes
1answer
230 views

Atropisomerism of naphthyl alcohol

In March's Advanced Organic Chemistry (6th ed.), it's stated that the above two are atropisomers. I don't get why is it so. How is the topmost $\ce{C}$ locked in its place? Surely, there's steric ...
0
votes
1answer
80 views

Reactions of differents halohydrins with tert-butoxide

I have two compounds (1​R,2​S)-3,3-dimethyl-2-bromocyclohexanol and (1​R,2​R)-3,3-dimethyl-2-bromocyclohexanol, both of them are treated with $\ce{KO^tBu}$ (a strong but bulky base) to form two ...
8
votes
1answer
388 views

What are the CIP rules for cyclic substituents?

Here's what I read on Wikipedia (section "Cycles"): To handle a molecule containing one or more cycles, one must first expand it into a tree (called a hierarchical digraph by the authors) by ...
2
votes
1answer
379 views

Why does 1,2-dimethylcyclohexane only possess three stereoisomers? [duplicate]

Why does 1,2-dimethylcyclohexane in chair form have only three stereoisomers? I understand that the trans isomer doesn't possess plane of symmetry and thus it has two stereoisomers. But my book says ...
3
votes
1answer
289 views

Is trans-1,2-dimethylcyclopropane optically active or not?

According to my book it is optically active, but no valid reason is given. But what I found is there exists an alternating axis of symmetry, and so my conclusion is the compound would be inactive or ...
-1
votes
1answer
147 views

Conditions for Chirality in optical isomerism [duplicate]

Is it necessary that any atoms which is chiral must have 4 different atoms around the central chiral atom(maybe it can be carbon if it's organic molecule) bonded to it? More specifically: I mean can't ...
8
votes
1answer
679 views

Can a lone pair be involved in cis/trans isomerism?

I was trying to find whether a molecule showed isomerism, and this is what I came up with. I thought this was the case as I took the nitrogen to be sp2 hybridised, thus trigonal planar (with the ...