Chemists uncover new role of a key base in organic synthesis

By Carol Clark | eScienceCommons | Oct. 15, 2014

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The collaboration of chemists from across three continents is a result of the Center for Selective C-H Functionalization (CCHF), an NSF National Center for Chemical Innovation headquartered at Emory.

An international team of chemists has discovered a new piece to the puzzle of how a powerful base used in organic synthesis, cesium carbonate, plays a pivotal role during a catalytic reaction.

The research, published by the Journal of the American Chemical Society, was led by Jamal Musaev, a theoretical chemist at Emory University, and Ken Itami, an experimental chemist from Nagoya University in Japan. Sun Yat-Sen University in Guangzhou, China, also contributed to the findings.

Many organic chemistry reactions are acid/base reactions, involving the exchange of positively charged hydrogen atoms. Acids donate the positively charged hydrogen and bases accept it.

The current research focused on the use of cesium carbonate as a base. Cesium carbonate has recently been observed to accelerate a particular class of catalytic reactions, a phenomenon termed the "cesium effect."

The use of cesium carbonate base and carboxylic acids co-catalysts have been shown to be critical in a number of recent carbon-hydrogen (C-H) bond functionalization reactions. The full story behind the impact of this base was previously not clear. It was known that the cesium base removed hydrogen protons, or scavenged acidic acid, from the solution, and was also involved in the exchange of ligands during a reaction, but these two factors did not explain the acceleration seen.

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