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Articles Archive for March 2008

Still In The RBF »

[30 Mar 2008 | 16 Comments | 8,063 views]

Tadano, Takao, Hayakawa, Yamada, Yamaguchi, Morita and Kawasaki, ACIEE, 2008, EarlyView. DOI: 10.1002/anie.200800253.
Mentioned in the comments, this tidy little synthesis features one hell of a tightly functionalised ring system, with seven contiguous stereocentres and a trans- trisubstituted olefin in a ten-membered ring. The biological activity seems impressive too: cytotoxicity and immunosuppressive activity, but the potency isn’t mentioned in this paper. This is actually the first synthesis of pestalotiopsin A, even though it’s recieved plenty of attention from the Procter and Paquette groups. Retro time:

Circumventing …

Still In The RBF »

[27 Mar 2008 | 46 Comments | 13,446 views]

Baran, O’Malley, Yamaguchi, Young and Seiple. ACIEE, 2008, EarlyView. DOIs: 10.1002/anie.200801138 10.1002/anie.200705913.
There’s been a bit of excitement in the comments about this synthesis, perhaps because it’s completion hints further towards a synthesis of Palau’amine, an ongoing passion of our community. The target of this synthesis contains the tetracyclic bisguanidine core common to these natural products, including eight contiguous stereocenters, making it quite a challenge. No biological activity is mentioned, but when the molecular architecture is as sweet at that, do you need another …

Still In The RBF »

[19 Mar 2008 | 11 Comments | 6,196 views]

Gaunt , Beck and Hatley, ACIEE, 2008, EarlyView. DOI: 10.1002/anie.200705005.
Another paper from Cambridge, this one from Matt Gaunt’s group. I’ve also seen development of the methodology behind this work progressing, and it’s nice to see it culminate in a smart and concise synthesis. Not much is mentioned about the natural product or it’s biological effects, other than “[it] mimic[s] the cellular effects of pacitaxel“, so are presumably also mitotic inhibitors. Retro time:

Perhaps the most obvious of disconnections is to cleave the amide bond in the …

Still In The RBF »

[13 Mar 2008 | 30 Comments | 13,936 views]

Paterson, Anderson, Dalby, Lim, Genovino, Maltas, and Moessner.ACIEE, 2008, EarlyView. DOIs: 10.1002/anie.200705565, 10.1002/anie.200705566.
Now I’ve been waiting for this ‘un… those of you who have been reading for a while will remember that I used to study at Cambridge University, and shared weekly meetings with the Paterson group. It’s certainly an ambitious target, with 21 stereocenters – and when they started the work, the absolute stereochemistry was yet to be assigned! Plenty of other groups are working on a synthesis of this beast, including …

Still In The RBF »

[10 Mar 2008 | 66 Comments | 28,906 views]

Zakarian and Stivala. JACS, 2008, ASAP. DOI: 10.1021/ja800435j.
What a beast of a molecule! This ‘un’s been around for a while, though, and has several synthesis to it’s credit – most notably that of Kishi. With a target this size, we’ve got to start with a thorough retrosynthesis. Splitting the molecule in half, separating the two polycyclic systems, the unification was planned via an alkylation of an aldehyde, which could be reoxidised for formation of the A-ring imine. RCM could then be used to complete …

Still In The RBF »

[5 Mar 2008 | 22 Comments | 11,359 views]

Overman, Dounay, Humphreys and Wrobleski. JACS, 2008, ASAP. DOI: 10.1021/ja800163v.
A far smaller target than the last we examined, but that’s still a very interesting architecture. Although the biological activity of this beast isn’t mentioned, similar natural products are found in traditional medicines, so perhaps it’ll do something interesting if you eat it. Their retrosynthesis is fairly ambitious, with a plan to use palladium couplings to complete two of the rings, and to do these reactions as part of a pair of tandem reactions.

The interesting chemistry …

Still In The RBF »

[3 Mar 2008 | 10 Comments | 6,301 views]

Nicolaou, Chen, Guduru, Sun, and Banerji. ACIEE, 2007, EarlyView. DOI: 10.1002/anie.200702243 JACS, 2008, ASAP. DOI: 10.1021/ja710485n.
You’d be forgiven for a feeling of déjà vu when looking at the post – yes, you have seen it before. Originally described in an Angewandte paper last year (which was discussed on this blog), Nicolaou and Chen achieved a smart, logical synthesis of the marine macrolide. The main problem was not the synthesis (which, at least from their description, was achieved without adversity), but the stereochemistry. The stereochemical …