Here’s the notice:
The following article from Angewandte Chemie International Edition, “Total Syntheses of Hexacyclinol, 5-epi-Hexacyclinol, and Desoxohexacyclinol Unveil an Antimalarial Prodrug Motif” by James J. La Clair, published online on February 9, 2006 in Wiley Online Library (http://onlinelibrary.wiley.com), has been retracted by agreement between the author, the journal Editor in Chief, Peter Gölitz, and Wiley-VCH Verlag GmbH & Co. KGaA. The retraction has been agreed due to lack of sufficient Supporting Information. In particular, the lack of experimental procedures and characterization data for the synthetic intermediates as well as copies of salient NMR spectra prevents validation of the synthetic claims. The author acknowledges this shortcoming and its potential impact on the community.
La Clair, of the Xenobe Research Institute, apparently presented the findings at the 231st American Cancer Society National Meeting in 2006.
The paper has been cited 11 times, according to CrossRef, as provided by Wiley.
Well-known blogger Derek Lowe has been writing about hexacyclinol since the paper appeared in 2006, and not in a flattering way:
The paper is remarkable in several ways, and not just because I’d never heard of La Clair. The synthesis is over 30 steps long, which is unfortunately not as uncommon as it should be. (I’m afraid that my bias against total synthesis is showing). But La Clair is the only author, which is highly unusual for such a large effort. And it must have been a large one, since the paper makes reference to starting on a molar scale and finished with over three grams of the penultimate intermediate. Experienced organic chemists will wonder if two or three decimal points have been misplaced there, but that’s what it says.
Lowe has much more, including what he calls a paragraph “for my fellow synthetic geeks.” He highlights one particular passage:
The strangest part of La Clair’s paper is its final footnote, added in proof. Here’s how it starts; make of this what you will: “The 1H NMR spectra for this Communication were determined by contract services. The spectra provided in the Supporting Information were collected by N. Voss (Berlin, Germany). The operator added the peak for CDCl3 to the spectrum of synthetic hexacyclinol (1), however, this was done incorrectly at 7.5 ppm and against the request of the author.” That doesn’t make a whole lot of sense. The NMR operator “added the peak” for solvent to a spectrum? Why? And he put the peak in at 7.5 ppm (the wrong place, for non-chemists)? With what, Photoshop? No, this is very strange indeed.
Lowe has posted a few more times on this case, including in 2009, about remaining questions.
We had a few questions ourselves — particularly why this retraction took six years. La Clair tells Retraction Watch:
This paper was retracted based on the fact that it lacked sufficient spectral data supporting the synthetic intermediates as well as detailed 2D NMR analyses on the isolated and synthetic final products; an omission that fueled considerable controversy. While many published synthetic and natural product isolation efforts can be found in the literature with similar lacks of data, the author elected to retract this paper due to the fact that this omission failed to meet the current expectations associated with the publication of total syntheses and natural product isolation. The author hopes that this incident inspires publishers, editors, reviewers and authors to advance more effective measures to check and require spectral data sets as a part of the publication process. In particular, there is currently a lack of tools for presenting raw data files along with publications.