School of Chemistry

Going for gold:Bristol researchers' new biaryl preparation method replaces palladium catalyst with gold

30 September 2012

Biaryls are compounds, featuring two directly connected benzene rings, that are essential building blocks in the creation of drugs and many modern materials such as LEDs.

Over the last two decades, methods for preparing biaryls have relied predominently on cross-coupling - a method in which two differentially pre-functionalised benzene rings are connected together in the presence of a catalyst, most often the precious metal palladium. However environmental concerns arising from the use of toxic metals and the requirement for pre-functionalisation of the coupling partners have led to a search for alternatives.

A new way to prepare biaryls using gold as a catalyst is described in the journal Science by University of Bristol researchers Professor Guy Lloyd-Jones, Dr Chris Russell and PhD student Liam Ball (from the Chemical Synthesis Doctoral Training Centre).

Formula for using gold catalyst
The reaction employs a low concentration of a gold catalyst to couple a simple aromatic ring with a non-toxic silicon-based partner, to generate biaryls at room temperature and under exceptionally mild conditions. A futher benefit is that the gold catalyst is cheaper than palladium and any gold residues are considered relatively benign.

'Gold-Catalysed Direct Arylation' by Liam T.Ball, Guy C. Llloyd-Jones, and Christopher A. Russell in Science