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Articles Archive for October 2006

Still In The RBF »

[30 Oct 2006 | 11 Comments | 7,352 views]

Nicolaou, Edmonds and Bulger. ACIEE, 2006, Early View. DOI: 10.1002/anie.200601872.
Another fantastic review in Angewantde this week from the team (or at least most of the team) that brought you Palladium Catalysis in Total Synthesis and Metathesis in Total Synthesis… this is building towards quite a bible! Not quite “Classics… III”, but still indispensable reading.

Still In The RBF »

[26 Oct 2006 | 15 Comments | 11,387 views]

Hanessian, Reddy and Chahal. Org. Lett.,2006, ASAP. DOI: 10.1021/ol0621710.
This C2 symmetric target shows an opportunity for a two directional synthesis, but as the other members of the family lack this feature, Hanessian et al used a more linear route for part of this synthesis. Most impressive (although by no means novel) was the methylation of the alkene, delivering two methyl groups in excellent d.r. Addition of lithium dimethylcuprate with TMSCl gave the anti product, which was enolised and alkylated with methyl iodide to give the …

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[24 Oct 2006 | 6 Comments | 4,740 views]

Porco and Zhu. Org. Lett., 2006, ASAP. DOI: 10.1021/ol062233m.
This concise synthesis of various members of the Mitorubin family by John Porco might be less controversial than my last post on his work, but it’s no less impressive. The centerpiece (for me at least) is a pair of copper-mediated transformations, appending the second ring and completing the core structure:

In the first reaction, the Cu(III)-spartine complex is used stoichiometrically, but to my eye doesn’t look too expensive… the methodology is discussed in this JACS from last year. The crude product from this …

Still In The RBF »

[18 Oct 2006 | 3 Comments | 5,173 views]

Sammakia, Mitton-Fry and Cullen. ACIEE, 2006, Early View. DOI: 10.1002/anie.200602601.
IHMO, not the most inventive synthesis of the month, but still a deft display of macrolide synthesis. The target (the imaginatively named RK-397) is a popular one, with previous syntheses by McDonald and Denmark. This is less surprising when one considers its antifungal, antitumor, and antibacterial activities! So to the retro:

All your favourite disconnection in one retrosynthesis! Okay, perhaps some of these are a given, but navigating the best disconnections amongst those polyol and polyene domains is pretty tricky! Once they’d …

Still In The RBF »

[16 Oct 2006 | 3 Comments | 2,390 views]

Last months best synthesis, voted for by you folks, was Batzelladine A; props to the Gin group

Still In The RBF »

[15 Oct 2006 | 16 Comments | 6,843 views]

Barrett, Larrosa, Silva, Gómez, Hannen, Ko, Lenger, Linke, White and Wilton. JACS, 2006, ASAP. DOI: 10.1021/ja0662671.
A nice, and short synthesis of this antibiotic/antifungal agent, using an interesting three-component-coupling strategy. First, the retro:

The larger substrate for this tranformation was assembled quickly, and the coupling completed by addition of methyl allyl grignard to the benzyne. The grignard generated in situ was then reacted with the aldehyde partner, completing the coupling.

The required diastereoisomer was recieved along with 21% of the undesired, but this was recycled using the aluminium species shown below. I’ve …

Still In The RBF »

[12 Oct 2006 | 22 Comments | 9,133 views]

Baran and Shenvi. JACS, 2006, ASAP. DOI: 10.1021/ja0659673.
As a comment on the previous synthesis pointed out, it’s interesting to see this paper in the same week as Corey’s synthesis of antheliolide, as both structures show interestingly complex fused ring structures. I’ve simplified the structure somewhat by flattening the ten-member ring, but with three cis- alkenes, the structure drawn in the paper is more realistic (and based on X-ray data). Baran’s approach to this complex system betrays some of his earlier schooling with Corey, using a rearrangement on a 5,5-fused system …

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[11 Oct 2006 | 18 Comments | 8,803 views]

Corey, Mushti and Kim. JACS, 2006, ASAP. DOI: 10.1021/ja066336b.
Another top synthesis of an interesting polycyclic target, this one with a complex nine-four-six ring system at its core. The structure was determined almost twenty years ago, but the synthesis has apparently slipped through the cracks, along with the absolute stereochemistry. No details on the activity of the target were given in the paper, but I’ve not read the isolation reference yet, so perhaps it does something… however, the synthesis is what we’re interested in
After eight steps, the workers achieved …

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[10 Oct 2006 | 5 Comments | 5,185 views]

Donohoe, Harris, Burrows and Parker. JACS, 2006, ASAP. DOI: 10.1021/ja0660148.
Oxidation action in this latest JACS from Tim Donohoe, completing the first synthesis of sylvaticin, a potent antitumor agent and nanomolar cytotoxicity target. The focus is, of course, the THF rings, lying four carbons apart, and with neighbouring hydroxyls. Their route hinges upon an interesting oxidative cyclisation, developed within the group and detailed in a previous methodology paper.

The fun begins with the synthesis of the cyclisation substrate, with the bulk of the work done by a pair of AD reaction performed …

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[9 Oct 2006 | 5 Comments | 5,118 views]

Burton, Sheldrake and Jamieson. ACIEE, 2006, Early View. DOI: 10.1002/anie.200602211.
I don’t want to blow our trumpet excessively, but we (that is the Burton group) have just published an Angewandte about total synthesis and structural reassignment of natural products. It’s based upon “elatenyne”, which we made, but it turns out that the NMR data of the synthetic sample didn’t match the biological sample. A bit of investigating has shown that perhaps the whole series has been incorrectly assigned…