New Catalysts of ruthenium (II) for selective hydration reactions and alkynes organonitrilos
What we offer:
Need or problem solving
Hydration of nitriles
Amides are elementary building blocks in organic synthesis, but also present, in themselves, many industrial applications such as drug. Consequently, the hydration of nitriles to generate the corresponding amides is a transformation of general interest. Traditionally this process has been carried out in the presence of strong acids or bases as catalysts, but these classical protocols have some drawbacks, including: (1) Reaction conditions drastic that exclude the presence of functional groups sensitive to pH's extremes (2) Difficult to stop the reactions in the product amide, which usually takes place and a subsequent hydrolysis step leads to the corresponding carboxylic acid, particularly in basic medium (see figure 2), (3) in addition, the final stage of neutralization both in acidic and in basic medium, leads to the formation of undesirable salts from the industrial point of view, as they cause pollution of final product and generate waste.
These drawbacks can be overcome by using transition metal complexes as catalysts. The activation of the C º N, takes place through coordination to the metal center, which accelerates the stage of hydration. In particular, ruthenium complexes are prominent in the evolution of such processes by three types of strategies: (a) the use of hydrophilic catalysts in aqueous medium, to avoid the disadvantages associated with organic solvents into employment, (b ) in the same direction, using pure water as solvent with hydrophobic catalysts and surfactants (surfactants) to facilitate solubilization of the latter, and (c) the use of anhydrous reaction media and organic compounds as a source aldoxime of water to expand the number of bodily functions compatible with the process so that the hydrolysis-sensitive groups are tolerated.
Hydration of alkynes
Hydration of alkynes, in turn, is a reaction that allows for a degree of carbonyls with optimal atom economy. Generally, these additions follow Markovnikov's rule (see diagram 3). So for example, a terminal alkyne can be hydrated to give the corresponding methyl ketone, using different acid catalysts and / or metal (usually salts of Hg (II), a strongly acidic pH). However, this protocol is very benign from an environmental perspective. On the other hand, the group recently achieved Grotjahn develop a general type bifunctional catalyst for the hydration of alkynes to aldehydes (anti-Markovnikov product) at neutral pH and with a high degree of selectivity, but using an organic solvent as a means of reaction. This process exceeds the hydroboration / oxidation of terminal alkynes as traditional strategy for alkynes from aldehydes, but again it would be desirable to go one step further in achieving a cleaner process, making it viable in aqueous medium. It could also expand its scope, the addition of amines.
On the other hand, it is possible to design more complex catalytic processes, in tandem or "one-pot" from functionalized alkynes with amines or alcohols, so that upon activation of the triple bond, cyclization occurs to give rise to indole or benzofuran type heterocycles. Again, Grotjahn group has pioneered this approach and their results suggest an unexpected mechanism based on the direct cyclization of ruthenium vinylidene formed as an intermediate in the catalytic cycle.
In particular type complexes have [RuX2 (p-cim) (L)] and [Rux (p-cim) (LL)] And with families phenanthroline ligands, diamino-triazine and amino-phosphine, active in the addition of water on nitrile and alkyne groups
These catalytic systems allow access to amides from nitriles and organ-ketones from alkynes, both selectively and minimizing side products
Applicability of the Technology
For the synthesis of amides, aldehydes, ketones or commercial interests.
Level of development
In research and development phase
Intellectual Property Rights
What are we looking for:
Companies engaged in its process synthesis of amides, ketones or aldehydes commercial interests.
For more information, visit the website of the research group at the University of Burgos Homogeneus Analyisis.
- ] Materials technology
- ] Anoganic substances
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