[lazipeter]

I want to ask about the naming of this alkene:


I thought it should be trans, 3-methyl 4-ethyl hept-3-ene
but I was wrong.
What the answer should be?

thanks

[azmanam]

substituents should technically go in alphabetical order.  but I think the more pertinent issue is it's not exactly accurate to use cis/trans for tri- or tetra-substituted alkenes.  Cis/trans really only works for di-substituted alkenes.  After that, you should use E/Z

[tangent1.57]

I'd say that this is trans 4-ethyl-3-methyl-3-heptene. 


What do you guys think?

[kd.gns]

like azmanam said cis/trans notation is not very effective for double bonds with more than two different substituents. In this case the molecule would be in the E conformation since the higher priority groups are on opposite sides of the double bond.

[orgoclear]

If you insist on using cis/trans then there will be a lot of confusion. I can say the compound is cis because the two ethyl substituents are on the same side. However as pointed out earlier, E/Z nomenclature is better in such cases