About a year ago, Sigma-Aldrich signed an exclusive licensing agreement with the University of Illinois, Urbana-Champaign. The technology developed by Dr. Martin Burke and coworkers involves the use of caged boronic acids called MIDA boronates in Suzuki cross-coupling reactions. The technology enabled historically challenging and even impossible couplings to take place. I was really excited to see the MIDA Boronates were recently featured in an article in Chem and Engineering News entitled: "New Way To Protect Unstable Boron Reagents"!

The article can be found at Chem and Engineering News (you will need to login as a user). 

Written by Dr. Sharbil J. Firsan

Raines and co-workers have prepared and investigated a series of phosphinothiols for their ability to mediate the traceless Staudinger ligation in water, and to be integrated with expressed protein ligation.  Of the three phophinothiols (1–3) that were tested, 1 and 2 gave disappointing results in good part due to their poor water solubility and the protonation of the nitrogen atom in their iminophosphorane intermediate in aqueous media.
Phosphinothiol 3 trihydrochloride is a water soluble, air-stable, odor-free, and easy-to-handle white solid, which mediates the rapid Staudinger ligation of equimolar amounts of azide and phosphine reagents in aqueous media at room temperature,  leading to >80% yields in solutions with pH ≥ 7.5.  It also undergoes transthioesterification with a thioester intermediate generated by recombinant DNA technology to produce a protein phosphinothioester that is poised to undergo the Staudinger ligation.

Tam, A.; Soellner, M. B.; Raines, R. T. J. Am. Chem. Soc. 2007, 129, 11421.

Written By: Mark Redlich, Ph.D.
Organic Letters just published on the web an article by Lipshutz detailing the first palladium-catalyzed allylic amination of allylic alcohols in pure water.  The reaction is easily achieved at room temperature with either dppf or biphep ligands when methyl formate was added to the reaction along with 2 wt % of the amphiphile PTS . A few cases result in the formation of limited quantities of the branched material, but most cases selectively favor the linear product.  The methodology was applied to the one pot synthesis of the antifungal naftifin, obtaining the target product in 83% isolated yield under exceptionally mild conditions.

If you’re interested in more information on PTS, check out http://tr.im/kcVq

Nishikata, T.; Lipshutz, B. H. Org. Lett. 2009, ASAP.

The conversion of alcohols to their corresponding carbonyl compounds is a critical functional group transformation and green processes, which can effect these transformations, are of significant interest.  While nitroxyl-based TEMPO has had a long-standing reputation as an environmentally friendly oxidant, the bulky nature of TEMPO’s piperidine skeleton precludes its use in sterically demanding environments. Iwabuchi and coworkers have shown that the related azaadamantane organocatalyst, AZADO (2-Azaadamantane N-Oxyl) exhibits enhanced reactivity over TEMPO in mild catalytic oxidations of secondary alcohols such as menthol.

Shibuya, M.; Tomizawa, M.; Suzuki, I.; Iwabuchi, Y. J. Am. Chem. Soc. 2006, 128, 8412.

Written by: Louis-Charles Campeau Ph. D.
Senior Research Chemist
Process Research & Development
Merck FrosstCentre for Therapeutic Research

For over a century, the rules that govern electrophilic aromatic substitution have been guided by the high Friedel-Crafts-type selectivity.  Electron-rich substituents direct ortho/para and electron deficient direct meta.  The Gaunt group at University of Cambridge has developed a new copper-catalyzed direct arylation reaction which, in contrast, selectively substitutes arenes at the meta position from an amido group.  This reactivity gives access to a wide variety of substitution patterns which can be challenging to synthesize otherwise.  Generally speaking, the reactions demonstrate higher efficency with electron-rich or neutral arenes rather than electron-deficient arenes. 

 
Phipps, R. J.; Gaunt, M. J. Science, 2009, 323, 1593

It is with profound grief that we say farewell to one of Aldrich Chemistry's long-term employees, Dr. Steven Branca. Steve passed away April 28, 2009 after a long struggle with liver cancer. Steve joined Aldrich Chemical Company in January 1981 as a Research Scientist after earning his Ph.D. in Chemistry under Professor Amos Smith at the University of Pennsylvania.

In rapid succession, Steve was promoted to Supervisor – Specialty Products, Manager – Research & Development, Director of New Products and ultimately to the position of Vice-President in May 1994. Subsequently, Steve provided leadership in Manufacturing and Business Development and most recently returned to a prior love of New Product Selection and Introduction.

Over his 28-year career Steve developed and mentored most of the current Manufacturing, Research & Development, and Marketing Management staff. He continuously displayed passion for his work, commitment to our organization and loyalty to everyone who dedicated themselves to its’ success.

Steve will be remembered as the premier theoretical / practical chemist of his time at Sigma-Aldrich. He was one of those special people that contributed greatly to the company’s success through shear force of will, hard work and love of chemistry.

We will miss his presence and friendship and honor his many contributions to Sigma-Aldrich.