Tag Archives: cubane

Publication of the week, number 1, 22 November 2013

I thought it would be good to suggest a publication of the week from amongst the ASAP material that I follow, a purely personal choice.

This week I picked the OPRD paper on the scale up of dimethyl cubane -1,4-dicarboxylate.

cubaneThe work appeared in Organic Process Research and development, 2013, doi.org/10.1021/op400181g . It was carried out by an Australian group, John Tsanaktsidis, Michael Falkiner, Stuart Littler, Kenneth McRae and Paul Savage from CSIRO and features a large-scale photochemical reaction which is very unusual to see in a scaled chemical process. Extending their previous work from 1997, they scaled the following reaction.

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As is the norm with such reactions the reaction requires high dilution to be successful. In this case they used a tailor made photochemical  reactor. A solution of 1 in methanol/water was pumped through the reactor at 4 L/minute and the conversion of 1 to 2 was noted as 1g/4 minutes of irradiation. This meant a total time of 173 hours. Further processing of 2 through the double Favourskii ring contraction required significant development but eventually delivered the di-sodium salt corresponding to the di-ester of cubane.

One needs to be careful with these cubanes as they are, due to the highly strained nature of the system quite energetic materials, the do-acid and ester being more stable than the parent hydrocarbon. However the energy released upon warming above the melting point is not insignificant.

This paper represents, for me, a good demonstration of the scale-up of several very difficult chemical reactions, including excellent descriptive paragraphs of the problems and solutions. They are to be congratulated on a very nice piece of  work.

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