Welcome Guest Search | Active Topics |

Tag as favorite
1001 Questions #194
Options
Previous Topic Next Topic
LoySonN
#1 Posted : Tuesday, July 27, 2010 9:17:14 PM
Rank: Member

Groups: Registered
Joined: 6/16/2010
Posts: 19

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
I know its hard to explain absolute configuration with just words, however, every time i try and determine absolute configuration I am finding that I always get the opposite configuration compared with the answer. For this question, the lowest priority group, H, is already set in the back, so no rotation is required. However, I was wondering can explain the remainder priority groups as to get an S configuration.

Thank you,
Natasha
Back to top
Report?
coordinator
#2 Posted : Thursday, August 19, 2010 9:41:44 PM
Rank: Member

Groups: Registered
Joined: 5/25/2010
Posts: 14

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
Hi Natasha - just remember to 1) correctly assign priorities, 2) determine if groups are clockwise (R) or counterclockwise (S), and 3) decide if the lowest priority group is away from you or towards you (if so, reverse the configuration).

In this question, NH2 takes priority 1, COOH priority 2, and the large benzene group priority 3. The orientation of these groups are in an S configuration and the hydrogen is going into the page. Hence the absolute configuration of the chiral carbon in (1)-dopa is S.

I hope this helps and if you (or anyone) have any additional questions, please call me at 780-988-1845 / e-mail: MatthewWard_Prep101@hotmail.com...

Thanks, Matt
Back to top
Report?
LoySonN
#3 Posted : Tuesday, August 24, 2010 2:38:24 AM
Rank: Member

Groups: Registered
Joined: 6/16/2010
Posts: 19

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
Thanks very much. Ive actually finished my mcat. No stereochemistry on mine, thank god...but i appreciate the help.
Back to top
Report?
Users browsing this topic
Guest
Tag as favorite
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Clean Slate theme by Jaben Cargman (Tiny Gecko)
Powered by YAF | YAF © 2003-2009, Yet Another Forum.NET
This page was generated in 0.046 seconds.