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Cis/Trans For Two Substituents on Same Carbon

Posted: Sat Mar 18, 2017 4:10 pm
by ntruong2H
If there are two different substituents on the same carbon, do we still have to indicate cis/trans? For instance, in the molecule 1-ethyl-1-methylcyclohexane, do we have to say trans (or E) - 1-ethyl-1-methylcyclohexane? Since I know the ethyl will be placed equatorial down and the methyl will be placed axial up (or vice versa depending on which carbon one chooses and which chair conformation one uses).

Re: Cis/Trans For Two Substituents on Same Carbon

Posted: Sat Mar 18, 2017 6:26 pm
by Chem_Mod
This is not possible. They would always be opposite of each other. You cannot specify anything at this point if they are on the same carbon.

Re: Cis/Trans For Two Substituents on Same Carbon

Posted: Sat Mar 18, 2017 6:28 pm
by ntruong2H
Chem_Mod wrote:This is not possible. They would always be opposite of each other. You cannot specify anything at this point if they are on the same carbon.


Okay thank you. Also, can we start with either chair conformation and then draw in the substituents? As long as the substituent is placed equatorially the answers should be equivalent right?

Re: Cis/Trans For Two Substituents on Same Carbon

Posted: Sat Mar 18, 2017 6:37 pm
by Chem_Mod
ntruong2H wrote:
Chem_Mod wrote:This is not possible. They would always be opposite of each other. You cannot specify anything at this point if they are on the same carbon.


Okay thank you. Also, can we start with either chair conformation and then draw in the substituents? As long as the substituent is placed equatorially the answers should be equivalent right?


Correct!