Nitrogen chemistry transformed
The element's prevalence has led to an explosion of new compounds at the heart of organic chemistry and medicinal chemistry. Among the recent discoveries in synthesis, the bulk of new catalytic reactions relate to C-H amination (addition of an amine) and alkene aziridination reactions. Aziridines have one amine group and two methylene bridges. The EU-funded SYNIC (Synthetic nitrene chemistry: New reactions and application) project devised several routes to improve the chemistry of nitrenes with an emphasis on finding new transformations. A first step was to develop an extremely efficient selective catalytic intermolecular oxyamination of simple alkenes. The new reactions yielded a variety of amino alcohols with an efficiency rate in the range of around 50 to 95 percent. With the mechanism of the basic oxyamination reaction well understood, the researchers then worked on a series of catalytic alkene reactions including diamination and carboamination. Intermolecular alkene carboamination is a very challenging transformation and very recent research from an American team has delivered the first successful result in 2015. The researchers are continuing to investigate the development of chiral dirhodium(II) complexes. Work using asymmetric intramolecular alkene oxyamidation resulted in only 40 % of yield of the enantiomer. Success in this area would mean the production of skeleton building methods for natural products and biologically active compounds. Promising results were obtained with rhodium bound nitrene as a catalyst for alkene difunctionalisation reaction. The research has shown for the first time that rhodium-bound nitrenes can act as Lewis acids and activate aziridines. The newly discovered feature of nitrenes by the SYNIC project promises to produce transformations that could have a high socio-economic impact through the development of new drugs. SYNIC researchers are of the opinion that extension of their work on nitrenes will provide transformations useful for industry as well as biomedicine. Project research has put the team at le Centre National de la Recherche Scientifique (CNRS) at the forefront of research in nitrene chemistry in Europe.
Keywords
Nitrogen, amine, nitrene, amination, alkene, aziridination, oxyamination, diamination, carboamination, chirality, rhodium, catalysis, Lewis acid
