[deutdeut]

The compound does not have any chiral carbons, but since the image and the molecule itself cannot superimpose each other, they are enantiomers. But my book said that they are not, why?

[AWK]

Set mirror parallel to carbon skeleton

[deutdeut]

Which carbon skeleton?

[Dan]

the mirror image is superimposable on the original structure.

[deutdeut]

why?and how I cannot know that from the structure I drew?

[Dan]

see above, the mirror image is related to the original by a simple rotation

[deutdeut]

I still can't understand the problem, can you explain a little bit more?

[Dan]

I'm afraid that the diagram is the best I can do without a model kit. I suggest you get a model kit, build the two structures and superimpose them.

[AWK]

Which carbon skeleton?

Carbon skeleton of trans-butene is flat

[deutdeut]

But the molecule itself is not a symmetric molecule, how can the image and molecule superimpose?

[AWK]

Trans-butene is a symmetric molecule. It shows a center of symmetry in the middle of a double bond.

[english]

deutdeut, in general the best way to tell whether you can have chirality is if your carbon is bonded to 4 unique groups.

This isn't always the case, but it works the majority of the time.



One case in which this doesn't necessarily work is in the case of allenes.

For example, the allene penta-2,3-diene exhibits chirality even though it has no asymmetric centers:

[AWK]

But allene is not flat!

[english]

But allene is not flat!

Yeah I know.  Some dumb image from a chemical supply site.  I don't know how to get my own images from ChemSketch on here.

 

[AWK]

[
Yeah I know.  Some dumb image from a chemical supply site.  I don't know how to get my own images from ChemSketch on here.

 

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