[energetica]

I have a question about E,Z nomenclature and if there is a cycloalkene.
In most cases I've done so far I usually had one cycloalkene (mostly cyclohexene) with 2 substituents that are the same (for example 2 methyls). I've figured out that in that case I should use cis or trans, but what if there are 2 different substituents (for example on one side there is methyl and on the other side Chlorine). Would it still be cis or trans or I would use E and Z (which should be used if the substituents are not the same)?

Other thing I was wondering is if we have deca-2,4,6,8-tetraene, while using E,Z nomenclature should I look for each Carbon connected with double bond or consider entire structure all together?

Thanks! =)

[bromidewind]

E/Z nomenclature is typically used when it is ambiguous as to which substituents are cis/trans. For instance, you can't tell which halogen is cis or trans in the two geometric isomers of 1-bromo-1-chloropropene. In my understanding, E/Z is becoming more common even when cis/trans is appropriate, so in your case, I would just use E/Z when naming your cycloalkenes.

As for deca-2,4,6,8-tetraene, you should always name the stereochemistry about each double bond.

Hope that helped!