Improved recipe for catalysts

Improved recipe for catalysts

Olefination of arenes via palladium-catalysed Mizoroki-Heck reaction...

Olefination of arenes is challenging because there are a number of positions on the aromatic ring to which the olefin can attach and there by leading to different isomers. One way is to follow the Heck reaction. The main criteria required for this reaction is that, the target carbon of the ring to be halogenated. And as synthetic chemists we know how tricky to get the halogenated compounds and that is why this reaction has limited applications. Its interesting to note that researchers from Scripps Research Institute have come with a novel procedure, where in there is no compulsion of halogenated compound.

As per the claim by the authors, the procedure is operationally simple, economical. The presence of a carboxyl group adjacent to the target C-H on the ring results in a phenomenon called the complex-induced proximity effect, which pulls the catalyst towards the relevant bond. In cases where the two ortho positions are equivalent, this approach alone can result in good yields of the desired product. When the substituents are different, the selectivity has been achieved by the use of amino acid-derived ligands between sterically and electronically similar ortho positions - which is really interesting...

http://www.rsc.org/chemistryworld/News/2009/November/27110902.asp

Cambrex wins the CPhI Innovation Award for its Continuous-Flow Microwave-Assisted Organic Synthesis technology

Cambrex wins the CPhI Innovation Award for its Continuous-Flow Microwave-Assisted Organic Synthesis technology

Mainly...

I am trying to concentrate mainly on "Med-Chemist" blog, but as and when I find interesting news (innovative research in the synthetic field), will continue with this blog toooo..

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New synthetic material (chameleon-like !) linked to opal ?

A new material could give a Chameleon a run for its money - it can rapidly change colour to match that of any in the visible spectrum.

The synthetic material can be likened to an opal, a mineral that owes its variety of colours to its layered structure: regions with a high refractive index, in which light travels slowly, are interleaved with regions with a low refractive index. Light waves with a wavelength - or colour - similar to that of the space between layers are scattered in a way that gives opal its iridescent sheen.

The chameleon-like "opal" developed by British and Canadian chemists has a similar layered structure. But their material goes one better than nature. It can rapidly shrink or swell to change the distance between its layered regions, changing the colour of light that it scatters (video).

Source :Newscientist, 23 December 2008.