Wednesday, October 17, 2007

IBX (not Irritable Bowl Xyndrome)

I really like oxidation reactions but, for some reason, many students get confused about how they work. It's not really different than any other reaction. It's just electrons moving from one place to another. The problem is that we usually think it is weird to push electrons toward an oxygen at the same time break electrons off of an oxygen. However, in nearly every oxidation of alcohols, this is happening. Of course the requirement is that you have something attached to the oxygen that is more electrophilic. For example, highly oxidized Cr or S or, in the case of IBX or Dess Martin oxidations, I. Well, I saw this interesting paper in Angew. Chem. this week that used IBX to do an interesting double oxidation. It is a nice approach to the saxitoxin family of natural products. I thought I would share the mechanism for your edification. We don't often think about oxidizing past the ketone stage, but under enolization conditions and with the right structural features (beta nitrogen), you can oxidize the alpha carbon.

Iwamoto, O.; Koshino, H.; Hashizume, D.; Nagasawa, K., ACIEE, Early View


4 comments:

Anonymous said...

For a moment I really thought your stomach is in trouble... Whooiii.. I have a question though, how did you do the nice chemdraw picture thingy? It's so xtal clear. Appreciate your advice. Thanks.

Javaslinger said...

Yes, you really do have excellent chem draw pics. What are you default settings for the molecules? How bout a tutorial?

Thanks,

Javaslinger

Greg the Chemist said...

Chemdraw settings:

Fixed lenght: 0.24 in
Bold Width 0.0334 in
Line Width 0.015 in
Margin Width 0.0266 in
Hash Spacing, 0.0416 in

I bold the text for my atom labels and make them size appropriate for the structures. Not too small, not too large.

Now, to get the picture to look good on the web has more to do with my Mac than Chemdraw.

I copy the chemdraw to Apple's Keynote program. I usually enlarge it there because it does a great job of rendering graphics and it scales the chemdraw vector graphics beautifully. Then I take a screen shot of the area I want to be a picture and upload that to Blogger.

Anonymous said...

But I don't have Apple... That darn fruit will cost me an arm and a leg! Cannot have pretty pretty picture... :<