Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Better connections through green catalysis

07.06.2010
Finely tuned nickel complexes combine important biomolecular precursors with high efficiency and low environmental impact

In chemistry, the nitro group (O-N=O) has a formidable reputation. The high reactivity that makes some nitro-bearing molecules potent explosives—think nitroglycerin or trinitrotoluene (TNT)—also enables NO2 to be extremely versatile in organic synthesis. Chemists can transform nitro groups into numerous other functionalities, such as biologically important amines or carbonyl compounds, providing a constant demand for new, efficient reactions involving these compounds.

Now, researchers led by Mikiko Sodeoka from the RIKEN Advanced Science Institute in Wako have developed an innovative way to connect organic molecules known as nitroalkenes and α-ketoesters together with precisely controlled geometries1. Because this synthesis uses an ‘environmentally friendly’ catalytic system, it can help create a broad range of molecules, including therapeutic natural products, under mild conditions.

Typically, reactions between nitroalkenes and α-ketoesters require hazardous liquids, generous quantities of catalysts, and very low temperatures to be successful. Instead, Sodeoka and her team were able to complete this chemical transformation at room temperature, with a non-toxic propanol solvent, by using small amounts of a nickel acetate catalyst —an advance with significant cost-saving and environmental-hazard reducing potential.

According to Yoshitaka Hamashima, a co-author of the paper, this discovery originated in the team’s previous finding that certain palladium complexes are stable and active catalysts, even in water2. After several trials, the researchers determined that nickel catalysts, which share similar properties to palladium materials, allowed the α-ketoesters to add to nitroalkenes with high yields and purity; over 90% of the final product corresponded to a specific stereoisomer, a molecule with a hard-to-achieve, geometrically distinct structure.

Hamashima explains that the nickel complexes are particularly effective because they recognize specific carbon atoms on the α-ketoesters and chemically activate them, generating products with precise frameworks. Furthermore, nickel has the right properties to maintain a delicate catalytic balance. “Nickel has a reasonable—not too strong, but not too weak—affinity towards nitro groups,” says Hamashima. “This affinity enabled the facile dissociation of the product from the catalyst, allowing high catalytic turnover.”

The high selectivity of this process, when combined with the mild reaction conditions, allowed the researchers to perform similar reactions on a broad range of molecules—including a highly efficient synthesis of the natural product kainic acid analog, a chemical that can bind to glutamate receptors within neuronal cells.

“Such selective activations are key to the success of our reaction,” says Hamashima. “Otherwise, undesired side reactions would occur when compounds with various functional groups are used as substrates.”

The corresponding author for this highlight is based at the Synthetic Organic Chemistry Laboratory, RIKEN Advanced Science Institute

Journal information

1. Nakamura, A., Lectard, S., Hashizume, D., Hamashima, Y. & Sodeoka, M. Diastereo- and enantioselective conjugate addition of α-ketoesters to nitroalkenes catalyzed by a chiral Ni(OAc)2 complex under mild conditions. Journal of the American Chemical Society 132, 4036–4037 (2010)

2. Sodeoka, M. & Hamashima, Y. Chiral Pd aqua complex-catalyzed asymmetric C–C bond-forming reactions: a Brønsted acid–base cooperative system. Chemical Communications 5787–5798 (2009).

gro-pr | Research asia research news
Further information:
http://www.rikenresearch.riken.jp/eng/research/6279
http://www.researchsea.com

More articles from Life Sciences:

nachricht Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>