Drawing Chair Structures - Organic Chemistry?

Question

I don't know how to draw the chair conformation of cyclohexane.
I know how to draw a chair, but not how to figure out where the substituents go...like where to put them after a ring flip and all that "fun" stuff..

detailed explanations or a website that shows it step by step. PLEASE

Anonymous · Accepted Answer

Dear Mona,

          I will try to make you understand this.

http://en.wikipedia.org/wiki/Cyclohexane_conformation

In the above link when you see chair conformation of cyclohexane you will find that every carbon of the cyclohexane ring has two hydrogens (or substituents), one of which is in axial conformation (shown in red colour) and other is in equitorial conformation (shown in blue colour).  When you flip a chair conformation to other chair conformation the axial substitutent becomes equitorial and equitorial becomes axial, this is also clear in the above link.

Now, to know in planar structure of cyclohexane with different substituent how to write it in chair conformation: 

Case 1:  if the substitutents are at carbon 1 and carbon 2:  if these substituents are cis to each other in planar structure then in chair form one of the substituent should be placed at axial and other at equitorial. whereas if these substituents are trans to each other then both the substituents should be placed as equitorial substituents or both of them should be placed as axial substituents (after flipping)

Case 2: if the substituents are at carbon 1 and carbon 3: if these substituents are cis to each other then both the substituents should be placed as equitorial or both of them should be axial (after flipping), whereas, if the substituents are trans then one of the substituent should be placed as axial and other as equitorial.

Case 3: if the substituents are at carbon 1 and carbon 4 (Note this case will be similar to the Case 1): if these substituents are cis to each other in planar structure then in chair form one of the substituent should be placed at axial and other at equitorial. whereas if these substituents are trans to each other then both the substituents should be placed as equitorial substituents or both of them should be placed as axial substituents (after flipping).


An Additional information: Generally in substituted cyclohexane the most stable chair conformation is the one in which most of the substituents are in equitorial position.  Bulkier substituens (like tert butyl group) always preffered to be in equitorial position.


I hope this will be clear to you now

You&#39;ve Got Dangled · Answer

http://ce.t.soka.ac.jp/stereo/ch4/ch4.materials.html

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Drawing Chair Structures - Organic Chemistry?

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