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Articles Archive for September 2006

Still In The RBF »

[28 Sep 2006 | 28 Comments | 7,981 views]

Overman, Limura, Paulini and Zakarian. JACS, 2006, ASAP. DOI: 10.1021/ja0650504.
I seemed to miss this one somewhere, probably in the move from my placement back to Cambridge. Anyway, this is a really nice synthesis of the popular guanacastapene targets (see this smart synthesis by Sorensen), using a unusual and funky Heck cyclisation. This reaction forms the main unifying transformation of the separate fragments, along with a 1,4 organocuparate addition. On with the synthesis!

I really liked this smart use of a Ireland claisen to set the stereochemistry about the quaternary centre in …

Still In The RBF »

[25 Sep 2006 | 5 Comments | 4,517 views]

Yep, with 38% of the vote, Zaragozic Acid was last month’s favourite synthesis, as voted for by you, the Tot. Syn. Reader. So congrats to the Rizzacasa group for being on the receiving end, and thanks to those of you who voted

Still In The RBF »

[21 Sep 2006 | 9 Comments | 6,863 views]

Ley, Bull, Balskus, Horan and Langner. ACIEE, 2006, Early View. DOI: 10.1002/anie.200602050.
A sweet and ultimately, short synthesis of this interesting target. I won’t bore you with a list of biological activity – suffice to say that it’s a very potent anti-fungal agent, and also anthelminthic. Their strategy was based around a unifying and diastereoselective [3+2] nitrile oxide cyclisation. This was used to impart the stereochemistry on one of the “down” via the inside alkoxy effect. The other could then be derived from the reduction of a ketone with Et2BOMe.

This …

Still In The RBF »

[19 Sep 2006 | 15 Comments | 10,416 views]

Gin, Arnold, Day, and Durón. JACS, 2006, ASAP. DOI: 10.1021/ja063860+.
Yet another top synthesis by David Gin, who really must be one of the most prolific total synthesisers this year! I really appreciate the fact that each molecule completed this year is completely different to the others, and they often contain hugely varying functionality. This time he has turned his attention on the batzelladines, working on structures A & D using some top new methodology. Focusing on batzelladine A, he uses their new methodology quite early-on, setting up the stereochemistry about …

Editorial »

[17 Sep 2006 | 3 Comments | 4,112 views]

Yup, we’ve got a poll now! It’s up to you folks – give a little back to the authors of thoses funky papers, and vote for your favourite synthesis of last month.

Still In The RBF »

[16 Sep 2006 | 28 Comments | 13,117 views]

Nicolaou, Nold, Milburn, and Schindler. ACIEE, 2006, Early View. DOI: 10.1002/anie.2006018677.
A very nice synthesis of this potent antibiotic (and believe me, we need new antibiotics), with top MRSA and VREF killing action. Using it’s dimeric nature to their advantage, they started with the synthesis of the monomers. Very early in this synthesis, they have need of a trisubstituted olefin, which they produce from the propargyl alcohol in a nice prep:

Now, I’ve used Red-Al many times to reduce an acetylene, and have been impressed with it, but this really nice. I …

Editorial »

[14 Sep 2006 | 15 Comments | 10,827 views]

Just a quick postlett to let those of you not at the ACS in San Francisco that La Clair got through his talk without a single question about hexacyclinol. Interesting. I’m not there either, but my informant quotes:
“I sat in on the LaClair lecture, and it was poised for big news. Seriously, it got very busy. I played safe and stayed in the lecture theatre 40 minutes before it was due to start, sitting through two distinctly average lectures from the Trauner group. I’m glad I did though, seriously, they …

Still In The RBF »

[13 Sep 2006 | 7 Comments | 7,026 views]

Chackalamannil, Shah, Ganguly, Chelliah, Kolotuchin, Buevich and McPhail, JACS, 2006, ASAP. DOI: 10.1021/ja065198n
An interesting synthesis by a group working at the Schering-Plough Research Institute. Certainly, this family of targets has received a load of attention by the pharma industry. Their synthesis starts with an aldehyde produced by Evans in his synthesis of (+)-A83543A, shown below:

This advanced fragment was elaborated with some nice, but fairly well-known chemistry to the cyclisation precursor. Treatment of this compound with base prompted little reaction, but heating in a microwave with HCl for one hour (quite …

Still In The RBF »

[11 Sep 2006 | 10 Comments | 5,986 views]

Hashimoto, Nakamura, Sugano and Kikuchi. ACIEE, 2006, Early View. DOI: 10.1002/anie.2006020307.
Some very smart cyclisation action in this paper by Hashimoto; the target is a component of a traditional Chinese herbal medicine, and their retrosynthesis hangs upon a powerful 1,3-dipolarcyclisation. The synthesis of the cyclisation precursor, whilst not trivial, was completed in a rather laborious fifteen steps. With this in hand, the cyclisation may commence!

Treatment of the diazo-compound with catalytic rhodium complex, and heating to 100 °C for five minutes allowed carbonyl-ylide formation, promptly follwed by 1,3-dipolar cyclisation. This tandem …

Editorial »

[5 Sep 2006 | 4 Comments | 6,164 views]

I won’t be posting anything new until next week – I’m going back to Cambridge to see a few days of lectures in honour of Dr. Stuart Warren’s retirement, all by ex-Warren group academics. Yes, he of The Great Green Book fame (amongst other texts he published). Thanks, Stuart, here’s looking forward to the next book!
In the mean-time, have a look this amazing quintuplet of publications by Stuart and Dr Fox in the last-but-one issue of OBC:
Diphenylphosphinoyl-mediated synthesis of ketones
Stuart Warren, David J. Fox and Daniel Sejer Pedersen
DOI: …