Refers to the spatial arrangement of atoms in a chemical entity.

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Utility of Bent's Rule - What can Bent's rule explain that other qualitative considerations cannot?

Does Bent's rule have any utility? I got a vehement earful for "NO." Points raised by my professor: Coulombic considerations can be used to rationalize bond angles, strengths, and lengths without ...
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Examples of intramolecular hydrogen bonding closing bond angles

Okay, we've established that intramolecular hydrogen bonding can exist in molecules, and doesn't always serve the purpose of closing the bond angle at least relative to other stereoisomers of the same ...
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What is Bent's rule?

I'm all bent out of shape trying to figure out what Bent's rule means. I have several formulations of it, and the most common formulation is also the hardest to understand. Atomic s character ...
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Why does nitrous acid exhibit (unexpectedly) different bond angles?

Data Point 1 - quantum chemical calculations http://nzc.iap.ac.cn/uploadpdf/Wang_et_al._CSB_2007a.pdf Key points in paper: There is some sort of interaction between the hydrogen and the terminal ...
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Inversion of Configuration - Opening of Epoxide

This doesn't look like a traditional inversion of configuration: At first I dismissed the textbook author as making a typo. But then I realized that this "typo" was repeated throughout the ...
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Is this disaccharide sucrose?

I want to know if the structure I drew is sucrose or an enantiomer of it. The One I Made: The one on internet:
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Gauche correction in Bensen group increment

I have difficulty understanding the use of gauche correction in Bensen group increment method to calculate the heat of formation. As an example, 4 times gauche correction (0.8 kcal / mol) is ...
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Racemic mixture of meso compound

My solution manual implied that we can have a racemic mixture of a meso compound. Is this possible? I was able to rotate the molecule to make it symmetrical. Sure, the bromination in the ...
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Enantiomers or Diastereomers?

The key tells me these are enantiomers. I however don't think they are; their chiral carbons' configurations aren't inverted - i.e. only one chiral carbon's R/S configuration changes! This ...
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Flipping a molecule vs. mirror behind compound

Why aren't these enantiomers? If you place a mirror behind the compound and look into the mirror, you get the second drawing.
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Why is the acyclic to cyclic rearrangement of Glucose formed via the C5 hydroxyl group?

In converting glucose from its acyclic form to either cyclic form (alpha or beta) why is the C5 hydroxyl group used instead of the bottommost hydroxyl group? Also, are these structures considered ...
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R, S Configuration and Branching - Which Path?

Which path do I take when we have a branched chiral center? None of the textbooks I've consulted adequately covers this or even provides an example problem in which there was branching. Consider ...
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R,S Configuration

I don't understand why this molecule is assigned S instead of R. The H is assigned a priority of 4; the methyl group on the chiral carbon gets 3; the left carbon gets 1 and the right carbon gets ...
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What is the canonical reference for studying stereochemistry?

I am well versed with all the named reactions and all of organic chemistry. I am quite weak in stereochemistry. What canonical text can I use to study this topic and connect with other parts of the ...
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How does Walter White make pure crystal meth using a non-stereospecific reaction?

In the fantastic TV series Breaking Bad, Walter White, the dying chemistry teacher, takes to making crystal meth (d-methamphetamine) by several routes. Initially, he uses the common small-scale route ...
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183 views

Molecular chirality and optical rotation

Why does having molecular chirality result in optical rotation? The dissymetry or chirality of molecules translates to the rotation of plane polarized light, the magnitude and direction depending on ...
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692 views

Finding chiral carbons in aromatic or cyclic compounds

I know that for a carbon to be chiral four different groups should be attached to that particular carbon. But, what about in the case of cyclic compounds? What's the method to check chirality if the ...
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129 views

Racemization of biphenyl compounds

How does the effect of heat and effect of substituents affect racemization of biphenyl compounds?
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Entropy and racemization?

The process of racemization of an optically compound is entropy driven and hence nature prefers a racemic mixture to an optically active one, which is consistent with the idea of the intuitive ...
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Why is the Wittig reaction syn stereoselective?

This question is meant for a simple (not stabilized) Ylide. Consider the classical mechanism for the Wittig reaction given on Wikipedia I am not able to understand why only one intermediate has ...
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acyclically stereocontrolled reaction: organolithium and 2-chiral compound

Aoyagi et al. (J. Am. Chem. Soc., Vol. 115, No. 24, p 11393) reported that the addition of 2-lithio-1,3-dithiane to the alpha-chiral (S)-2-Acetylpiperidine gives the (2 S,3 S)-configured product. It ...
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The Evans auxiliary: rotational freedom of the benzyl group - stereoselectivity still guaranteed?

I created the L-Phenylalanine based Evans auxiliary bearing a benzyl group with help of a molecular model set and got into some questions. The structural formula will do: As I suppose a low ...
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480 views

Effect of periodic acid on cyclohexane derivatives

Periodic acid (per-iodic acid, $\ce{HIO4}$ ) cleaves vicinal diols(to carbonyls) via a cyclic intermediate. Due to the cyclic intermediate, it needs a syn configuration for the $\ce{-OH}$ groups for ...
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How do I determine the absolute configuration experimentally?

Let's say I synthesized or isolated a chiral molecule and want to know the absolute configuration (R or S) of that molecule. I could obviously solve the structury by X-Ray crystallography, but that's ...
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How do you separate enantiomers?

There are some stereochemical reactions that result in the presence of enantiomers. When moving forward with a practical organic synthesis, how does one usually separate them in order to continue with ...