A catalytic scalable Pauson–Khand reaction in a plug flow reactor
Csflowchem in collaboration with Universidad San Pablo CEU has developed a catalytic and scalable Pauson-Khand reaction using a plug flow reactor (PFR). In the paper published by the Chemical Communications of the RCS, several examples of catalytic intra and intermolecular Pauson-Khand reaction are described. The Pauson–Khand reaction (PKR) is a formal [2+2+1] cycloaddition of an alkyne, an alkene and a carbonyl unit to give a cyclopentenone. Until the late 1990s it was mediated by a stoichiometric amount of metal, generally cobalt. Many catalytic protocols that use different cobalt and other metal complexes have appeared, some of them lacking a general scope. In our case the reaction was carried out with 5% of cobalt octacarbonyl and just 3 eq of carbonmonoxide at 20 bar in a PFR. With around 10 min of residence time and moderate temperatures, the conversions are excellent, and the isolated yield are very good in most of the examples.
This paper is a great example of what are the capabilities and the experience of Csflowchem in gas involved flow chemistry. The carbon monoxide and hydrogen are two of the most common gases used in organic chemistry for reactions of hydrogenation or carbonylation, with hetero or homogeneous catalyst systems, and Csflowchem has the experience to offer this technique to their clients. We are able to develop gas involved reactions using a very small amount of gas: in the examples described in the paper of PKR, we obtained very good results using just 1.5 eq of carbon monoxide. In our experience, some hydrogenation could be carried out using just 4 eq of hydrogen. These are the greatest advantages in security that the flow chemistry provides to the chemists in this moment and Csflowchem offers to their customers.
To consult the paper link to: http://pubs.rsc.org/en/content/articlelanding/2017/cc/c7cc01749a?iscitedby=True#!divAbstract