Why are carbons of Inositol chiral centers?
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I was asked to draw all possible stereoisomers of Inositol (1,2,3,4,5,6-cyclohexanehexol). To obtain the answer I had to assume that all six carbons of the molecule are asymmetric, which (bearing in mind possible molecular symmetry) results on the following nine stereoisomers:1
The problem is that I fail to see why these carbons can be considered chiral centers. Given:
"The most common cause of quirality in an organic molecule, altough not the only one, is the presence of a carbon atom bonded to four different groups [...]. These carbons are now named chiral centers [...]" 1
The chirality of the molecule is not the reason of my doubts, I can see that the only chiral isomers are D- and L- chiroinositol. Since all carbons in the ring possess a hydroxil group, ¿can they not be considered to be bonded to equivalent substituents, making them symmetric? ¿Is the possibility of the -OH groups to be above or below the plane of the ring what makes them assymetric?
1: From Wikipedia
[2]: McMurry, John. Organic Chemistry. CENGAGE Learning, 2008. 7th edition.
organic-chemistry stereochemistry isomers chirality heterocyclic-compounds
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I was asked to draw all possible stereoisomers of Inositol (1,2,3,4,5,6-cyclohexanehexol). To obtain the answer I had to assume that all six carbons of the molecule are asymmetric, which (bearing in mind possible molecular symmetry) results on the following nine stereoisomers:1
The problem is that I fail to see why these carbons can be considered chiral centers. Given:
"The most common cause of quirality in an organic molecule, altough not the only one, is the presence of a carbon atom bonded to four different groups [...]. These carbons are now named chiral centers [...]" 1
The chirality of the molecule is not the reason of my doubts, I can see that the only chiral isomers are D- and L- chiroinositol. Since all carbons in the ring possess a hydroxil group, ¿can they not be considered to be bonded to equivalent substituents, making them symmetric? ¿Is the possibility of the -OH groups to be above or below the plane of the ring what makes them assymetric?
1: From Wikipedia
[2]: McMurry, John. Organic Chemistry. CENGAGE Learning, 2008. 7th edition.
organic-chemistry stereochemistry isomers chirality heterocyclic-compounds
asked 3 hours ago
RosciscoRoscisco
163
New contributor
Roscisco is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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Seven of the nine inositols are achiral. Any carbons lying in a plane of symmetry are in achiral environments (r and s). Those carbons not in a plane of symmetry are in chiral environments (R and S). I Googled "inositols chirality" and found this: ursula.chem.yale.edu/~chem220/chem220js/STUDYAIDS/isomers/…
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– user55119
2 hours ago
add a comment |
$begingroup$
I was asked to draw all possible stereoisomers of Inositol (1,2,3,4,5,6-cyclohexanehexol). To obtain the answer I had to assume that all six carbons of the molecule are asymmetric, which (bearing in mind possible molecular symmetry) results on the following nine stereoisomers:1
The problem is that I fail to see why these carbons can be considered chiral centers. Given:
"The most common cause of quirality in an organic molecule, altough not the only one, is the presence of a carbon atom bonded to four different groups [...]. These carbons are now named chiral centers [...]" 1
The chirality of the molecule is not the reason of my doubts, I can see that the only chiral isomers are D- and L- chiroinositol. Since all carbons in the ring possess a hydroxil group, ¿can they not be considered to be bonded to equivalent substituents, making them symmetric? ¿Is the possibility of the -OH groups to be above or below the plane of the ring what makes them assymetric?
1: From Wikipedia
[2]: McMurry, John. Organic Chemistry. CENGAGE Learning, 2008. 7th edition.
organic-chemistry stereochemistry isomers chirality heterocyclic-compounds
asked 3 hours ago
RosciscoRoscisco
163
New contributor
Roscisco is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I was asked to draw all possible stereoisomers of Inositol (1,2,3,4,5,6-cyclohexanehexol). To obtain the answer I had to assume that all six carbons of the molecule are asymmetric, which (bearing in mind possible molecular symmetry) results on the following nine stereoisomers:1
The problem is that I fail to see why these carbons can be considered chiral centers. Given:
"The most common cause of quirality in an organic molecule, altough not the only one, is the presence of a carbon atom bonded to four different groups [...]. These carbons are now named chiral centers [...]" 1
The chirality of the molecule is not the reason of my doubts, I can see that the only chiral isomers are D- and L- chiroinositol. Since all carbons in the ring possess a hydroxil group, ¿can they not be considered to be bonded to equivalent substituents, making them symmetric? ¿Is the possibility of the -OH groups to be above or below the plane of the ring what makes them assymetric?
1: From Wikipedia
[2]: McMurry, John. Organic Chemistry. CENGAGE Learning, 2008. 7th edition.
organic-chemistry stereochemistry isomers chirality heterocyclic-compounds
organic-chemistry stereochemistry isomers chirality heterocyclic-compounds
asked 3 hours ago
RosciscoRoscisco
163
New contributor
Roscisco is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
RosciscoRoscisco
163
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Roscisco is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
RosciscoRoscisco
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asked 3 hours ago
RosciscoRoscisco
163
asked 3 hours ago
RosciscoRoscisco
163
163
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Seven of the nine inositols are achiral. Any carbons lying in a plane of symmetry are in achiral environments (r and s). Those carbons not in a plane of symmetry are in chiral environments (R and S). I Googled "inositols chirality" and found this: ursula.chem.yale.edu/~chem220/chem220js/STUDYAIDS/isomers/…
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– user55119
2 hours ago
add a comment |
$begingroup$
Seven of the nine inositols are achiral. Any carbons lying in a plane of symmetry are in achiral environments (r and s). Those carbons not in a plane of symmetry are in chiral environments (R and S). I Googled "inositols chirality" and found this: ursula.chem.yale.edu/~chem220/chem220js/STUDYAIDS/isomers/…
$endgroup$
– user55119
2 hours ago
$begingroup$
Seven of the nine inositols are achiral. Any carbons lying in a plane of symmetry are in achiral environments (r and s). Those carbons not in a plane of symmetry are in chiral environments (R and S). I Googled "inositols chirality" and found this: ursula.chem.yale.edu/~chem220/chem220js/STUDYAIDS/isomers/…
$endgroup$
– user55119
2 hours ago
$begingroup$
Seven of the nine inositols are achiral. Any carbons lying in a plane of symmetry are in achiral environments (r and s). Those carbons not in a plane of symmetry are in chiral environments (R and S). I Googled "inositols chirality" and found this: ursula.chem.yale.edu/~chem220/chem220js/STUDYAIDS/isomers/…
$endgroup$
– user55119
2 hours ago
add a comment |
1 Answer
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Consider 2,3-butanediol.
This compound has 2 stereocenters. The meso version of this compound is achiral. However, there are still two stereo centers. As drawn, the left one is (R) and the right one is (S). It is precisely because these two stereocenters are identical but opposite in configuration that leads the molecule to be meso.
A carbon center is asymmetric if it has 4 different substituents regardless of whether or not the whole molecule is chiral. The ring substitution is such that the centers around the ring are not identical (including when you look at stereochemistry--for example, (R) has higher priority than (S)). This of course isn't enough to help you easily make stereochemical assignments for all of the centers of inositol, but hopefully, this allows you to understand why the centers are still chiral centers.
As an aside, there are a few centers that cannot be chiral because they lie on a mirror plane. Interestingly, though changing the configuration of the center produces a different molecule. These centers are call pseudochiral and we label them with lower case r and s.
answered 1 hour ago
ZheZhe
12.5k12550
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$begingroup$
Consider 2,3-butanediol.
This compound has 2 stereocenters. The meso version of this compound is achiral. However, there are still two stereo centers. As drawn, the left one is (R) and the right one is (S). It is precisely because these two stereocenters are identical but opposite in configuration that leads the molecule to be meso.
A carbon center is asymmetric if it has 4 different substituents regardless of whether or not the whole molecule is chiral. The ring substitution is such that the centers around the ring are not identical (including when you look at stereochemistry--for example, (R) has higher priority than (S)). This of course isn't enough to help you easily make stereochemical assignments for all of the centers of inositol, but hopefully, this allows you to understand why the centers are still chiral centers.
As an aside, there are a few centers that cannot be chiral because they lie on a mirror plane. Interestingly, though changing the configuration of the center produces a different molecule. These centers are call pseudochiral and we label them with lower case r and s.
answered 1 hour ago
ZheZhe
12.5k12550
$endgroup$
add a comment |
$begingroup$
Consider 2,3-butanediol.
This compound has 2 stereocenters. The meso version of this compound is achiral. However, there are still two stereo centers. As drawn, the left one is (R) and the right one is (S). It is precisely because these two stereocenters are identical but opposite in configuration that leads the molecule to be meso.
A carbon center is asymmetric if it has 4 different substituents regardless of whether or not the whole molecule is chiral. The ring substitution is such that the centers around the ring are not identical (including when you look at stereochemistry--for example, (R) has higher priority than (S)). This of course isn't enough to help you easily make stereochemical assignments for all of the centers of inositol, but hopefully, this allows you to understand why the centers are still chiral centers.
As an aside, there are a few centers that cannot be chiral because they lie on a mirror plane. Interestingly, though changing the configuration of the center produces a different molecule. These centers are call pseudochiral and we label them with lower case r and s.
answered 1 hour ago
ZheZhe
12.5k12550
$endgroup$
add a comment |
$begingroup$
Consider 2,3-butanediol.
This compound has 2 stereocenters. The meso version of this compound is achiral. However, there are still two stereo centers. As drawn, the left one is (R) and the right one is (S). It is precisely because these two stereocenters are identical but opposite in configuration that leads the molecule to be meso.
A carbon center is asymmetric if it has 4 different substituents regardless of whether or not the whole molecule is chiral. The ring substitution is such that the centers around the ring are not identical (including when you look at stereochemistry--for example, (R) has higher priority than (S)). This of course isn't enough to help you easily make stereochemical assignments for all of the centers of inositol, but hopefully, this allows you to understand why the centers are still chiral centers.
As an aside, there are a few centers that cannot be chiral because they lie on a mirror plane. Interestingly, though changing the configuration of the center produces a different molecule. These centers are call pseudochiral and we label them with lower case r and s.
answered 1 hour ago
ZheZhe
12.5k12550
$endgroup$
Consider 2,3-butanediol.
This compound has 2 stereocenters. The meso version of this compound is achiral. However, there are still two stereo centers. As drawn, the left one is (R) and the right one is (S). It is precisely because these two stereocenters are identical but opposite in configuration that leads the molecule to be meso.
A carbon center is asymmetric if it has 4 different substituents regardless of whether or not the whole molecule is chiral. The ring substitution is such that the centers around the ring are not identical (including when you look at stereochemistry--for example, (R) has higher priority than (S)). This of course isn't enough to help you easily make stereochemical assignments for all of the centers of inositol, but hopefully, this allows you to understand why the centers are still chiral centers.
As an aside, there are a few centers that cannot be chiral because they lie on a mirror plane. Interestingly, though changing the configuration of the center produces a different molecule. These centers are call pseudochiral and we label them with lower case r and s.
answered 1 hour ago
ZheZhe
12.5k12550
answered 1 hour ago
ZheZhe
12.5k12550
answered 1 hour ago
ZheZhe
12.5k12550
answered 1 hour ago
ZheZhe
12.5k12550
12.5k12550
add a comment |
add a comment |
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$begingroup$
Seven of the nine inositols are achiral. Any carbons lying in a plane of symmetry are in achiral environments (r and s). Those carbons not in a plane of symmetry are in chiral environments (R and S). I Googled "inositols chirality" and found this: ursula.chem.yale.edu/~chem220/chem220js/STUDYAIDS/isomers/…
$endgroup$
– user55119
2 hours ago