[Mitch]

Don't piss this man off (Manfred Christl):

The recent retraction of two papers regarding diaza[12]annulenes by Yamaguchi et al. and Shi et al. from separate groups have strengthened the argument for stronger peer review and more thorough literature review by authors. http://dx.doi.org/10.1002/anie.200704704
But anyone can be an armchair synthetic chemist and point fingers at what should have been done after the fact. The easiest finger to point, is presumably between 7 coauthors, 4 reviewers, 2 editors no one ran the appropriate literature searches to find that these reactions are known and yield products with exactly 1/2 the mass as those reported in the papers. But, now we come to the bitter truth in modern chemical research, we simply do not perform the thorough literature searches of yester'year. Some will say this is a problem, but assuming those 13 scientists are typical of scientists of today then it simply isn't a fair commentary to make. So, I thought it would be more beneficial to reread the papers and see if I would have come to the same conclusions given the same series of data, as I'm oblivious to heterocyclic chemistry in general and the Zincke reaction in particular, and have a typically topical background like most chemistry graduate students (I'm a Nuclear Chemist after all).

First up the Yamaguchi paper: http://dx.doi.org/10.1021/ol061585q
The title is the One-Pot Synthesis of N-Substituted Diaza[12]annulenes. Just looking at the title, we should be expecting ¹H,¹³C-NMR, definitely MS data, and likely a crystal structure since the molecule would have two cationic-like centers. Picture shown below.

As can be seen in the structure this monstrosity should have some serious pi-pi stacking possibilities, and isolating crystals shouldn't have been too problematic, but none are isolated. An image of their NMR data for the structure above is below.

It would be at this point that the little voice in my head would be like, "hmm.... why do I have aromatic proton peaks? I should probably count those pesky buggers again. Yup, 12 delocalized electrons." If one is postulating that this is antiaromatic, then one hallmark of antiaromatic hydrogens, located on the outside ring, are that they shift upfield (lower ppm) and lie to the right of 8 ppm and likely 7ppm. So, it would have been at that point where the paper would of confused me.

Second up the Shi paper: http://dx.doi.org/10.1002/anie.200702140
The title is the [12]Annulene Gemini Surfactants: Structure and Self-Assembly. So, we should be expecting yucky yellow oils, and with the word structure, perhaps even a crystal structure. The molecules examined are shown below.

Independently, they confirm the odd aromatic protons of Yamaguchi and they obtained a yellow powder, not necessarily an oil, but well within reasonable expectations. They did some calculations with Gaussian and discovered the results below.

The expected distorted structure is seen in II but lied 1.7 kcal/mol higher in energy than I. This is just odd, for a cyclic antiaromatic system we should expect to see 2^nd order Jahn-Teller distortions shift the molecule away from planarity and this was not seen by calculations.  This is where the authors and reviewers can be faulted, at that point some one should have suggested an experiment to see whether the NMR peaks would move upfield as a function of temperature. As scientists, we love making graphs, and that would have been a neat confirmation of both the structural predictions from calculations, and an easily verifiable hypothesis.

In summary, I don't feel it is fair to fault the authors, reviewers, editors for not knowing every obscure heterocyclic named reaction. However, it is prudent upon all of us to ask the right questions about our research, to put-off deadlines if necessary, and to apply our full intellect and diligence to our experiments.

Mitch

Some Armchair commentary here:

• Pipeline: Neat wish it were true, kids these days, Exciting Nonsense Wins Another One
• Coronene: Cornies 2007: Molecule of the Year

[Ψ×Ψ]

(In order to prevent my head from exploding, you need a grammatical lobotomy.  I can ignore simple mistakes, but...you're using the wrong word.  Whenever you're tempted to write "may OF" or "should OF"...replace OF with HAVE.) 
Whenever I see a kinky structure like this suggested, I look at the supporting information.  If I don't see a CIF, I am skeptical at best.

[Mitch]

I was being rushed out the door when I wrote the post. I've smoothed out the rough edges for the time being and likely will clean up the language further.

[Mitch]

http://www.wsu.edu:8080/~brians/errors/couldof.html

[lemonoman]

It would be interesting to hear what the supervisors (or whoever applied for the project's funding) were saying when the manuscript was being written up.  My guess is that they had good ideas for why they got the results that they did, and decided not to pursue it further?

Literature reviews can be cumbersome.  I feel for these people.  If I was a graduate student (presumably some of the co-authors are), I'd have just told myself, "My prof didn't know any better.  Why should I have?" 

[excimer]

The authors forgot thermodynamics. You break aromaticity of two pyridine rings to generate an antiaromatic ring under thermodynamic control (refluxing ethanol for 12h)- that's just silly.