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[22 Jan 2012 | 16 Comments | 30,550 views]
Stenine Pt. 2

Zhang, Chen, Chen, Xie. ACIEE, 2011, 51, 1024. DOI: 10.1002/anie.201106587  
Second time around for Stenine on TotallySynthetic - the first synthesis I blogged takes us back to 2008, and Aube’s neat work focusing around a tandem Diels-Alder / Schmidt reaction. This latest publication moves the research to Kunming, China, the home of it’s use as part of Chinese herbal medicine.  That doesn’t alter the core of the synthetic strategy, though, as Hongbin Zhang seems to agree with Aube that building the cyclohexane core first is the key to this target.
Zhang, however, prefers the use of a …

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[14 Jan 2012 | 33 Comments | 21,720 views]
Fusarisetin A

Li, Deng, Zhu, Lu, Yu. JACS, 2011, ASAP. DOI: 10.1038/nchem.1196  
Just take a quick look at that target and consider that the synthetic route I’m about to summarise took thirteen steps.  I’m fairly stunned – I read the top-line number in the abstract, and immediately thought that they must have started with an advanced intermediate or degredation product, but no – the synthetic action (like many natural product syntheses) begins with Citronellal.  Sure, only three of the rings are carbocyclic, but there’s a lot going on here, so lets get into …

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[7 Dec 2011 | 23 Comments | 21,270 views]
Taxane Skeleton

Baran, Mendoza, Ishihara. Nature Chem., 2011, EarlyView. DOI: 10.1038/nchem.1196   
Hmm… I’m still not convinced about whether I should really post on this paper, but I’m interested in it, so to hell with the rules!  What we’ve got here is a sort-of meta-synthesis; Baran doesn’t actually make any of the taxane natural products, but demonstrates an extremely neat synthesis of a potential common precursor.  The theory behind the work is related to previous Baran diatribes, where he points out that too many steps in syntheses simply oxidise and reduce the same …

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[30 Oct 2011 | 38 Comments | 19,786 views]
Daphmanidin E

Carreira, Weiss. ACIEE, 2011, EarlyView. DOI: 10.1002/anie.201104681   
Now that’s a busy polycyclic ring-system!!  Three five-membered rings, two six-membered rings and one seven (depending, of course, on how one counts the ring sizes.  Anyone read the IUPAC Gold Book last night?) – adding up regardless of maths to one hell of a synthetic challenge.  And there’s even some token biological activity to aim for – this bad-boy has some moderate vasorelexant acitivity next to rat aorta.  (When the paper mentions ‘moderate’ activity, we can be pretty sure it does very little indeed…) …

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[4 Sep 2011 | 64 Comments | 21,460 views]
Maoecrystal Z

Reisman, Cha, Yeoman. J. Am. Chem. Soc, 2011, ASAP. DOI: 10.1021/ja2073356 
A busy couple of weeks in the Reisman lab, it appears – really nice syntheses of the Cepharatines and 8-Demethoxyrunanine in Angewandte (doi: 10.1002/anie.201104487), but I decided to blog this tasty synthesis of Maoecrystal Z.  Of course, this isn’t the first member of that family that I’e blogged – the seminal synthesis of Maoecrystal V made my December 2010 column in Chemistry World.  I remember when I wrote that piece that the pseudo-3D structure used to represent the target annoyed …

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[20 Aug 2011 | 28 Comments | 12,471 views]
Axinellamines Pt. II

Baran, Su, Rodriguez. J. Am. Chem. Soc, 2011, ASAP. DOI: 10.1021/ja206191g
When does a person or groups work in a particular area of total synthesis become pedestrian, or even dull? This may sound harsh (especially as he’s a really nice guy), but Paterson’s (at Cambridge) work on macrolides isn’t doing it for me any more. Conversely, Baran’s work in the area of pyrrole-imidazole alkaloids is still facinating, even though I’ve blogged about it more than a few times! What we’re looking at here, though, isn’t …

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[14 Aug 2011 | 19 Comments | 16,731 views]
N-Methylwelwitindolinone C

Garg, Huters, Quasdorf, Styduhar. JACS, 2011, ASAP. DOI: 10.1021/ja206538k
Technically beaten to the finish-line by Rawal (JACS in March), but still the first asymmetric synthesis of the Welwitindolinone family, this synthesis is one of many contributing to a hell of a year for Neil Garg.  I think the key to the synthesis was picking the perfect starting point – and dealing with poor yields that get you seriously further forwards.
That critical starting point is  fantastically smelling (S)-Carvone.  Not only does this make the lab (and presumably the chemist, his notebook, …

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[6 Aug 2011 | 17 Comments | 15,203 views]
Omphadiol

Romo, Liu. ACIEE, 2011, 50, 7537-7540. DOI: 10.1002/anie.201102289
Guest Blogger: SPF
What if I’d ask you to synthesize this little molecule with six neighbouring stereocenters from biologically available material? Oh, by the way you can’t use any protecting groups and keep it short! Sounds impossible? Not according to Romo et al.. They’ve achieved the synthesis of this stereo-dense molecule in 10 steps from (R)-carvone (Mmmhhh spearmint). (+)-Omphadiol belongs to the africanane (guess where they grow) family of sesquiterpenes. Its brothers and sisters show some significant bioactivity, but due to insufficient …

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[29 Jul 2011 | 10 Comments | 14,579 views]
Trigonoliimines A-C

Guest Blogger: See-Arr-Oh
Han and Movassaghi, JACS 2011, 10768-10771. DOI: 10.1021/ja204597k ; Qi, Bao, and Tambar, JACS 2011, 10050-10053. DOI: 10.1021/ja203960b .
It’s not too often JACS publishes total syntheses anymore, since their role as a general chemistry journal means every newly built molecule competes against quantum dots, in silico simulations,  or new battery materials. So you can imagine my utter shock and delight at finding not one, but two almost back-to-back syntheses in the past month!  First, the Porco / Ready combination of Kibdelone C, followed closely by two syntheses …

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[2 Jul 2011 | 23 Comments | 19,797 views]
Loline

Trauner, Cakmak, Mayer. Nat. Chem., 2011, 3, 543. DOI: 10.1038/nchem.1072
Simple tricyclic morpholine derivative with four stereocenters. Can’t take that much effort, can it? Well, yes it can – and it’s amazing how tricky this little beastie is! Trauner explains in the informative introduction that only one successful synthesis has been completed – taking twenty steps to get to the racemic target. Clearly that leaves the team in Germany with a lot of room for improvement.

The team made the first intermediate in the scheme …