Cheap works better than Noble!

6 Feb 2017. NUS chemists have developed new iron-catalysed reactions for producing molecules used in pharmaceutical drug production.

Vinylboronate esters are synthetically versatile intermediates used widely in the production of complex drug molecules. These boronate esters are traditionally prepared from pre-activated alkenes, but this is a complex process that requires extra steps in synthesising the molecule and may produce extra waste. A more efficient method, the one-step synthesis of these boronate esters directly from alkenes through C-H borylation reaction, is more desirable. However, such reactions can only work with the use of noble metal catalysts which are usually expensive and in short supply. This limits the use of the one-step synthesis process.

A team led by Prof Shaozhong GE from the Department of Chemistry, NUS has developed a way of realising vinylic C-H borylation using an iron catalyst. The iron catalyst shows much higher activity and selectivity than noble metal catalysts for multiple-substituted alkenes. This iron-catalysed reaction demonstrates the first direct vinylic C-H borylation of alkenes by using cheap, non-toxic, and earth-abundant metals.

Prof Ge and his research team are continuing this work, focusing on developing catalytic organic transformation with catalysts derived from widely available cheap, and non-toxic base metals. They are developing reactions to produce synthetically useful building blocks for the synthesis of drug molecules, pharmaceutical candidates and organic materials. Their work would enable more efficient production of chemical compounds, leading to higher productivity and cheaper medications.

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Figure shows the iron-catalysed vinylic C-H borylation reaction which was developed.

 

Reference

Wang C; Wu C; Ge S* “Iron-Catalyzed E-Selective Dehydrogenative Borylation of Vinylarenes with Pinacolborane” ACS CATALYSIS Volume: 6 Issue: 11 Pages: 7585-7589 DOI: 10.1021/acscatal.6b02654 Published: 2016