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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 14 of 14. This is the beginning of the thread.
Posted by Deneb on September 30, 2008, at 17:19:09
Help. LOL
I'm having difficulties visualizing, and drawing the resulting products from a Zimmerman-Traxter transition state!
It's the difference between a Z enolate with an aldehyde and an E enolate with an aldehyde. How do I tell what is where and how do I know whether it's SYN or ANTI?
Aaaah! LOL
I think I built the model wrong. LOL
Posted by Kath on September 30, 2008, at 17:24:41
In reply to Help, anyone know about Zimmerman-Traxter?, posted by Deneb on September 30, 2008, at 17:19:09
Holy Smokeroo Deneb,
I do NOT understand one single thing that you said.
You must be VERY VERY VERY smart. And I hope you remember that if ANYone ever tries to indicate otherwise to you!!!!
You ROCK!!
luv, Kath
Posted by Deneb on September 30, 2008, at 17:43:54
In reply to Re: Help, anyone know about Zimmerman-Traxter? » Deneb, posted by Kath on September 30, 2008, at 17:24:41
Aw man, I thought you could help me! LOL
I must not be that smart if I'm not getting this! LOL
OK, I think I built the right model this time and I understand the steric interactions, but HOW DO I FIND OUT WHETHER IT IS SYN OR ANTI?? Aaaaahhhhh!
Posted by llurpsienoodle on September 30, 2008, at 18:54:16
In reply to Help, anyone know about Zimmerman-Traxter?, posted by Deneb on September 30, 2008, at 17:19:09
Ummm...
My favorite kind of chemistry is the kind that I eat.
Sorry I cannot help you, but I DO know the number of a chemistry-anonymous hotline. (joke)
well, good luck deneb*
:/
Perhaps larry hoover will see your cry for help...
Posted by Deneb on September 30, 2008, at 23:21:07
In reply to Re: Help, anyone know about Zimmerman-Traxter? » Deneb, posted by llurpsienoodle on September 30, 2008, at 18:54:16
Sorry, I just figured out my prof either spelled it wrong or I copied it down wrong.
My tutors are too busy to tutor me this week!
I went to psychcentral's chat and chat with someone who said he knows organic chem, but all he did was type in some chemistry related things.
He said something about pesticides and C+. I don't know what he's talking about.
OK, I looked in the index of my Claydon text. I *think* I've figured it out.
OK, so in the Zimmerman-Traxler transitional state, if the substituent that determines chirality is in the pseudoaxial position, it turns into a syn aldo and if it's in the pseudoequatorial position, it turns into an anti aldo??
Posted by Deneb on September 30, 2008, at 23:22:54
In reply to Re: Help, anyone know about Zimmerman-Traxler?, posted by Deneb on September 30, 2008, at 23:21:07
Aldo is a shoe store. ROFL
Posted by Deneb on October 1, 2008, at 18:30:20
In reply to Re: Oops, not aldo, aldol LOL, posted by Deneb on September 30, 2008, at 23:22:54
Without my tutor, figuring out this stuff is hard!
I need to practice practice practice.
Oh man, if I ever understand all this and can put it together, that would be really cool.
Right now we are learning how to do reactions that select for one enantimer, R or S. It's neat because this was chemstry developed in the 80's, so relatively recent.
Posted by Phillipa on October 1, 2008, at 19:10:44
In reply to Re: I don't think I'm going to do very well, posted by Deneb on October 1, 2008, at 18:30:20
No idea what you're talking about you're so very intelligent. Phillipa
Posted by Kath on October 1, 2008, at 20:13:01
In reply to Re: I don't think I'm going to do very well, posted by Deneb on October 1, 2008, at 18:30:20
Jeez Louise Deneb,
It's all Greek to me!! LOL
Kath
yer one smart cookie
Posted by Deneb on October 2, 2008, at 18:01:35
In reply to Re: I don't think I'm going to do very well » Deneb, posted by Kath on October 1, 2008, at 20:13:01
I need to study, but I'm not studying!
Posted by Deneb on October 3, 2008, at 13:25:45
In reply to Re: Help, I'm procrastinating, posted by Deneb on October 2, 2008, at 18:01:35
I figured out Zimmerman Traxler transition states! Woohoo!
Posted by Deneb on October 3, 2008, at 22:12:00
In reply to Re: Yay! I figured it out!, posted by Deneb on October 3, 2008, at 13:25:45
I'm just really excited about organic chem. LOL.
Just sharing my excitement.
But maybe no one cares. LOL.
Maybe no one knows what the heck I'm raving about. Rofl
I get excited about things easily.
I love organic chem.
Posted by Larry Hoover on October 4, 2008, at 16:20:56
In reply to Re: Help, anyone know about Zimmerman-Traxler?, posted by Deneb on September 30, 2008, at 23:21:07
I'm glad you figured it out, as you've already been tested on it. I'm glad you worked it out on your own, using models. I don't think there's a better way to learn.
This particular effect wasn't in any of my texts, even though it's fifty years old. Wiki actually has a pretty good description of it, and what controls the stereoselectivity of the product. http://en.wikipedia.org/wiki/Aldol_reaction
Lar
Posted by Deneb on October 4, 2008, at 16:44:50
In reply to Re: Help, anyone know about Zimmerman-Traxler? » Deneb, posted by Larry Hoover on October 4, 2008, at 16:20:56
I wrote my midterm exam today and I actually did not even open up my model kit. I heard lots of the characteristic popping noise from models being built and unbuilt from the rest of the students, but I didn't need to use the models.
On the test it asked for lots of transition states, there was the Zimmerman Traxler of an enolate with an aldehyde, the deprotonation of ketones, it asked us to explain the difference between how a thermodynamic versus kinetc product arise.
This is the end of the thread.
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