Spanish chemists reveal their 'most efficient' catalyst for crucial transformation.

A simple and effective catalyst for an important organic transformation has been disclosed by three chemists at the Universidad de Oviedo in Spain. José Gimeno, Victorio Cadierno and Sergio García-Garrido looked at the ability of a readily available ruthenium complex to convert allylic alcohols into saturated aldehydes or ketones, and they struck gold.

An interest in green chemistry or, as the authors put it, in developing 'catalytic processes with atom efficiency in environmentally friendly media and with industrial applications' provided all the motivation necessary. They chose to investigate this particular reaction, they say, because it is useful but generally requires two steps and is rarely successful in water.

The chemists show how their catalyst can quickly and completely synthesise ketones from allylic alcohols in one step and in water. The ruthenium complex they chose as a catalyst is stable in water and comes from a group of such complexes that are widely used in organic synthesis. Unusally, their ruthenium is in the +4 oxidation state; ruthenium (II) complexes are more commonly used.

'As far as we know this is the most efficient catalyst described to date for this important transformation,' says Gimeno. Furthermore, he claims, the catalyst remains active even in the presence of conjugated dienes, which generally inhibit isomerisation catalysts, and can be used repeatedly without losing its activity.

The research is welcomed by Hans-Ulrich Blaser, chief technology officer at Solvias, a Swiss scientific services compa ny based in Basle: 'The unusually active ruthenium complex.will definitely be of synthetic value, albeit more for the preparation of saturated ketones.'

But he cautions : 'What remains is the challenge to apply this new catalyst to multifunctional 'real-world' substrates.'

Caroline Evans