Sunday, February 18, 2007

RACIOC 22 Highlights Part I

So I'm finally recovering from the conference followed by a pile of grant proposals and other stuff. Overall the conference was pretty good. The conference was a joint physical organic and organic conference and they attempted making sessions of general interest to everyone which is commendable but it didn't really work for me most of the time. Nevertheless, a lot of very good stuff was presented. One of the highlights was a talk given by Professor Michael Sherburn from the Australian National University (ANU) in Canberra entitled "Everything You Ever Wanted To Know About Synthesis". He's an amazing entertainer. I just wish he would start singing and dancing too. He really reminded me of Frank Sinatra and his chemistry is absolutely brilliant - Diels-Alders all the way. He showed some interesting work using dendralenes (e.g. DOI: 10.1021/ja053772+): Kerrie Austin working for Professor Banwell (also at ANU) gave a good presentation on her work with (-)-Complicatic Acid (see structure below) and (+)-Hirsutic Acid C. I've mentioned this work before and there wasn't much I hadn't seen before. However, I have to show my complete ignorance regarding Mander's reagent. It's quite a useful reagent for doing stuff like this (didn't spot the yield for this reaction though): The conference really turned out to be a useful reagents and techniques conference. Professor Erick Carreira from ETH in Z├╝rich gave an excellent presentation as always. He showed some really interesting work using sulfamic acid as an ammonia equivalent in allylic substitution reactions. He showed a whole bunch of reactions and it looked very convincing indeed. Here's an asymmetric example using one of Ben Feringa's ligands (unoptimised, unpublished etc.):With some development this stuff looks like it may be quite useful. To be continued....D!

13 comments:

Petr said...

methyl cyanoformat is usually called mander's reagent.

Daniel Sejer said...

Thank you! I knew I got the name wrong. I'll fix it straight away. Cheers, D!

Tex said...

Mander's reagent is great (but relatively expensive), however, the beta ketoester that you show in your blog is commercially available (dirt cheap) or readily prepared by a Dieckmann.

Petr said...

actually, i forgot particular advantage of cyanoformate over chloroformate :(

Daniel Sejer said...

Yes I realise that that particular application of Mander's reagent is overkill. I think Kerrie's structure was more complex but can't remember the other substituents on the cyclopentanone. I don't have a clue when you would use Mander's reagent instead of a chloroformate. D!

Anonymous said...

perhaps you should read the original paper by Mander and Sethi to find out...

Daniel Sejer said...

Do you have the reference for the Mander paper? D!

Daniel Sejer said...

L.N. Mander and S.P. Sethi, Tetrahedron Lett. 1983, 24, 5425-5428. The reason for using methyl cyanoformate is that it works! Chloroformates give mixtures of O- and C-alkylated material. Yields in the paper are ranging from 65 to 96%. D!

Anonymous said...

Why are some people so helpful and others, generally those under the anonymous tag, such arses. Thanks Dan for the ref and low down.

Russ said...

That's a neat amination reaction. Surely, that's a BINOL-based ligand, and not two separate naphthols, as shown (otherwise it wouldn't be chiral). And was there a Lewis acid in the mix, or is the sulfamic acid itself helping to ionize the allylic alcohol?

Daniel Sejer said...

Errrr yes...he did quite a bit of racemic aminations too and I'm mixing the structures up. I'll add the missing bond straight away. There was no Lewis acid in the mix. However, the reaction only works if DMF is present. He proposed a funky mechanism. I'll add that too for good measure. D!

Daniel Sejer said...

I'm losing it man. I haven't been blogging for three weeks and there are mistakes all over the place. The addition of a bit of [IrCl(COD)]2 would probably make that allylic amination happen sometime this century. D!

Russ said...

Ah. With those changes, the whole thing seems more understandable. Still a pretty cool reaction.