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Articles tagged with: Wittig

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[7 Aug 2010 | 15 Comments | 20,248 views]
Cortistatins A (J, K and L) Pt. IV

Myers, Flyer, Si. Nat. Chem., 2010, AOP. DOI: 10.1038/nchem.794
Cortistatin is one of those targets like platensimycin that has attracted an almost unhealthy synthetic lust in the last few years, with three previous appearances in these interwebs (Baran, Nicolaou, Shair).  The reasons for both are the same – both have remarkable biological profiles, and both are of challenging complexity.  However, both are now what I’d call mature targets – in that the best disconnections have been tried, and that there are unavoidable methods that feature in most routes.  However, that …

Still In The RBF »

[17 Jun 2010 | 11 Comments | 12,729 views]

Jung, Chang, Org. Lett., 2010, ASAP DOI: 10.1021/ol1009762.
Although the number of actual steps in a formal synthesis is (or at least should be) smaller than in a full total-synthesis, I often feel that the actual work is harder.  Afterall, one is directly comparing ones work with that of another researcher, and in this case Michael Jung has got his work cut-out.  There aren’t many professors whose work is truly that daunting, but Clayton Heathcock is one of them. Jung’s work intercepts the Heathcock synthesis eight steps from then …

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[3 Mar 2010 | 67 Comments | 23,862 views]
Echinopine A

Nicolaou, Chen, Ding, Richard. JACS, 2010, ASAP. DOI: 10.1021/ja9093988.
As I twittered the earlier today, redrawing KC’s crayonisation of Echinopine A took quite a while – but I think one needs to see both representations to get a feeling for the complexity here.  The unique [] carbon skeleton is pretty special – apparently enough that no biological rationale is given for this work.  Perhaps I spend too much time looking a biological assay results these days…
So with nothing else for me to witter-on about, I’ll get into …

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[24 Jan 2010 | 62 Comments | 25,032 views]

Gin, Perl, Ide, Prajapati, Perfect, Duron. JACS, 2010, ASAP. DOI: 10.1021/ja910831k.
When I see targets containing guanidine moieties these days, I immediately think of David Gin, which goes to show how much he owns that motif just now.  Looking back into the murky past of Tot Syn, an earlier post covered Gin’s synthesis of Batzelladine A, which was fairly guanidine-tastic.  This bad-boy only has one, but with a bit of “anticancer, anti-HIV, antifungal, and Ca2+ ion channel blocking [activity]“, that grant-form presumably filled itself, especially at MSKCC.  However, …

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[13 Jun 2009 | 56 Comments | 16,547 views]
Napyradiomycin A1

Snyder, Tang, Gupta. JACS, 2009, 131, 5744. DOI: 10.1021/ja9014716.
Okay, it’s taken me far too long to get around to this article – I actually wrote the Chemdraw back when this article was in ASAP… but other stuff got in the way, like a little Nature paper from Baran.  However, it’s a damned nice paper, so it’s impossible for me not to go back and look at it properly.  The target here is an halogenated natural product, isolated from Streptomyces bacteria – so it’s not too surprising …

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[16 Feb 2009 | 17 Comments | 12,854 views]
Norhalichondrin B Pt. I

Phillips, Jackson, Henderson, Motoyoshi. ACIEE, 2009, EarlyView. DOI: 10.1002/anie.200806111. Article PDF Supporting Information Group Website

As I said in the last post, it was a rather quiet fortnight for total synthesis, at least as the big journals go. However, I think Andy Phillips can feel justified in his absence when he’s been cooking molecules like this ‘un up. Norhalichondrin B is part of the halichondrin family, isolated about twenty years ago – plenty of time for a bit of synthetic action, kicked off by Kishi back in ’92. Impressively, the synthesis hasn’t been entirely academic, with the peeps at Eisai Pharma also working on analogues. So how to start (lots of grant-application forms…)?