Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: HuàXué on October 27, 2009, 11:48:45 PM

Title: Help with (E)-(Z) System
Post by: HuàXué on October 27, 2009, 11:48:45 PM

When assigning priorities, do we follow the same rules as the rules in the R/S-designation?

Title: Re: Help with (E)-(Z) System
Post by: Scatter on October 28, 2009, 03:16:32 AM

Only in the fact that you assign priority based on the atoms that are directly bonded to the carbons, working outwards if they are the same.

With R and S designation you are assigning 4 different priorities (1-4) around a chiral center and with E Z designation you are assigning two priorities on each half of a double bond (high or low).  If someone cares to explain that better, please do, I'm a student too.

Title: Re: Help with (E)-(Z) System
Post by: movies on October 28, 2009, 11:13:43 AM

Yes, the order you give to groups is exactly the same for _E/_Z and _R/_S.  The comparisons you make are a little different, as Scatter pointed out, but when determining which group has the highest priority, the method is the same.

Title: Re: Help with (E)-(Z) System
Post by: tinapratiwi on November 01, 2009, 08:41:35 PM

I think the explanation of the Scatter already includes all.