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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: whyohme on August 12, 2012, 04:53:51 PM

Title: Z, E naming
Post by: whyohme on August 12, 2012, 04:53:51 PM

Hi, everyone, im having a trouble with Z,E nomenclature.   (part c)

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So the solution of this question is :   (3E)-3-(1-methylethyl)-1,3-pentadiene.

I dont understand why it is 3E instead of 3Z.

The left upper part of the double bond is "Higher",  the left lower part is "lower" obviously cuz there is no carbon attached to

I have no idea about the right part..


besides, why the first double bond is not showing "z" or "e" in the solution ?

Thanks!

Title: Re: Z, E naming
Post by: RaInBowDaSh1488 on August 12, 2012, 08:49:08 PM

The EZ for the carbon 3 is a bit tricky IMO. I think that it is E because of the double bond containing substituent and how Cahn Ingold Prelog assigns priority in cases involving double bonds.

Regarding the first double bond; it has two hydrogens on one side of the double bond. You can't really apply E or Z to the first double bond because there are two identical substituents on one side of the double bond.