Good Orgo Practice

[Dental Jarry]

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I found this website and thought I would share with everyone.

http://chemistry.boisestate.edu/people/richardbanks/organic/mc/mcquestions317.htm

 

[alanan84]

Thanks for posting this!

This may sound stupid but I don't understand this:

4. The most stable conformational isomer of trans-1-ethyl-2-methylcyclohexane will be...

​

I don't understand how C is trans...

 

[prsndwg]

Thanks for posting this!

This may sound stupid but I don't understand this:

4. The most stable conformational isomer of trans-1-ethyl-2-methylcyclohexane will be...

​

I don't understand how C is trans...

Methyl is facing up and Ethyl is facing down. Dash and wedges.

 

[vlct0ria]

I need all the practice I can get for orgo...thanks for the link! 👍

 

[Dental Jarry]

Thanks for posting this!

This may sound stupid but I don't understand this:

4. The most stable conformational isomer of trans-1-ethyl-2-methylcyclohexane will be...

​

I don't understand how C is trans...

when looking at these you determine cis or trans by whether the methyl and ethyl are up or down, not both axial or both equitorial. So for C, Ethyl is equitorial and the H is axial, and the Et is obviously below the H..On the other hand even though Me is also equitorial and the H is axial, this time the equitorial position is above the axial (ME is above H). This makes it trans. For cis the Me and Et would have to be either both up or both down. Hope that clarifies alittle

 

[alanan84]

when looking at these you determine cis or trans by whether the methyl and ethyl are up or down, not both axial or both equitorial. So for C, Ethyl is equitorial and the H is axial, and the Et is obviously below the H..On the other hand even though Me is also equitorial and the H is axial, this time the equitorial position is above the axial (ME is above H). This makes it trans. For cis the Me and Et would have to be either both up or both down. Hope that clarifies alittle

As sad as it may sound, I seriously don't remember learning that in Ochem. Thanks, that made perfect sense!