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Articles Archive for December 2006

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[21 Dec 2006 | 4 Comments | 3,432 views]

It’s that time to put the mag-sulphate down, and pack-up those TLC plates… or in the Burton Group’s case, move labs. Yup, the new location of Burton Towers is in Oxford’s CRL, having packed up the lab and moved it all through this week. Even the little NMR tubes. And how swish are our new labs :). Here’s a few more interesting photos:

So now it’s time to go on our seasonal hiatus, and for me to thank you all for reading and contributing to the …

Still In The RBF »

[17 Dec 2006 | 5 Comments | 3,167 views]

Last months best synthesis, voted for by you folks, was Acutiphycin ; props to Ryan and the Jamison group.
Also, I’ve uploaded a copy of November’s posts, converted to a PDF. So if you missed anything, or want to read the post offline, click on the PDF link at the top… I hope it’s useful!

Still In The RBF »

[17 Dec 2006 | 6 Comments | 5,549 views]

Burke, Lucas and Gopalsamuthiram. ACIEE, 2006, EarlyView. DOI: 10.1002/anie.200603656.
We covered the reasons for making Phorboxazoles fairly recently in James White’s synthesis of the Phorboxazole A last month. I also pointed out that these natural products have been fairly popular, with a further two syntheses of this beast, by Evans and Zhou. At first glance of this paper, I wasn’t particularly impressed, as much of the work has been seen in other syntheses, and seemed pretty standard chemistry. However, looking beyond the retro and into the fragment synthesis, a fine body …

Still In The RBF »

[15 Dec 2006 | 10 Comments | 4,820 views]

Danishefsky, Cook, and Polara. JACS, 2006, ASAP. DOI: 10.1021/ja0670254.
A very quick synthesis of this compact yet complex natural product, abliet in it’s racemic form. Danishefsky et al. decided to use a rather impressive oxidative dearomatization to construct one ring, allowing a further intramolecular Diels-Alder reaction to complete the core. But they had to make the cyclisation substrate first:

Functionalisation of the aromatic ring was completed easily, with a formylation and bromination of a m-hydroxy-phenol delivering the electrophilic Stille component. Coupling to an allyl silane, and elimination of a mesyl group then …

Still In The RBF »

[14 Dec 2006 | 12 Comments | 5,751 views]

Evans, Nagorny, McRae, Sonntag, Reynolds, Vounatsos, Xu. ACIEE, 2006, EarlyView. DOIs: 10.1002/anie.200603652, 10.1002/anie.200603653, 10.1002/anie.200603654.
No biological data given as a raison d’etre, so we’ll focus on the fact that this is one bad-ass structure, ripe for a bit of aldol-bashing. Indeed, over the three communications outlined above (why not one article?), Evans et al go seriously aldol-tastic in the synthesis of this 41-member macrolide. So, to the retro (and probably the most complex I’ve drawn so far:

Now that’s what I call a disconnection approach! It’s all in the execution from …

Still In The RBF »

[11 Dec 2006 | 2 Comments | 4,482 views]

Ramachandran, Srivastava and Hazra. Org. Lett. 2006, ASAP. DOI: 10.1021/ol062737k.
Not a lot of new methodology, just a well put together synthesis of Dictyostatin. For the uninitiated, the target is a microtubule stabilizing cancer chemotherapeutic agent, which, unlike paclitaxel, does not bind to P-glycoprotein. This means that the resistance mechanisms operating on this binding mode are inoperative, making this and the related discodermolide increasingly popular targets.
Of course, other syntheses exist, with pioneering work by Paterson and Curran, and a more recent synthesis by Phillips. The approach used by Ramachandran is somewhat …

Still In The RBF »

[10 Dec 2006 | 5 Comments | 10,253 views]

Ley, Maddess, Tackett, Watanabe, Brennan, Spilling, Scott and Osborn. ACIEE, 2006, EarlyView. DOI: 10.1002/anie.200604053.
It’s been in the works for quite a while, but Steve Ley’s synthesis of Rapamycin has just been published. This complex beast has a multitude of biological activities, including an interesting immunosuppressive profile, resulting in clinical usage following organ transplantation. So, unsurprisingly, it’s been the target of many projects, with complete total syntheses published by Smith, Danishefsky, Schreiber and KCN.
So what makes this one different? Well, it does have one of the most interesting macrocyclisations I’ve seen …

Still In The RBF »

[6 Dec 2006 | 8 Comments | 4,583 views]

Clark, Hayes, Wilson, and Gobbi. ACIEE, 2006 , EarlyView. DOI: 10.1002/anie.200602780.
Another medium-ring ether synthesis, but using completely different methodology to last months excellent synthesis by Kim. But Steve Clark (now at “WestChem“, having moved from Nottingham) should know these species pretty well, having worked with Andy Holmes… Anyway, this is a great read, so on with the synthesis (no retro; you’ll see why…).

To build up some functionality for their crucial rearrangement, they used a great Sm mediated reductive cyclisation, starting with the acyclic precursor. …

Still In The RBF »

[4 Dec 2006 | 10 Comments | 13,269 views]

Sorry folks; no new posts for the next few days, ’cause I’m off to the Pfizer Poster Competition in Canterbury. Much chemistry will be discussed, along with a little eating and probably quite a lot of drinking. Do say “hi” if you are also attending, but otherwise, I’ll have a new post later this week
Here’s a gratuitous photo of Pfizer’s Sandwich site…

P.S. don’t miss this ACIEE by Forsyth – this might be a really nice synthesis!

Still In The RBF »

[1 Dec 2006 | 27 Comments | 7,525 views]

Roush and Va. JACS, 2006, ASAP. DOI: 10.1021/ja066663j.
Nope, this isn’t déjà vu (or the film), this really is another synthesis of amphidinolide E, the second this month (the first was by Lee in Korea). This time it’s Bill Roush from Scripps, using some their own methodology to construct that THF. So, first the retro:

As you can see, some of the disconnections are more obvious than others, but I assure you, their methodology isn’t “shoe-horned” in… The top-half of the molecule was discussed first, preparing the substrates for that funky [3+2], …