Ellen Phiddian
Cosmos science journalist
A bond between a carbon atom and a hydrogen atom is a special thing. Very strong, and therefore highly inert, it’s very difficult to interfere with.
The carbon-hydrogen (C-H) bond features in almost all biological molecules, padding them from unwanted reactions.
But breaking the C-H bond can open up many new avenues in synthetic chemistry..
A team of chemists has manipulated C-H bonds to make a complicated, naturally-occurring molecule, from simple ingredients.
“It just opens up a lot of chemistry that you wouldn’t have considered before,” says Professor Brian Stoltz, at the California Institute of Technology, USA, and co-author on a paper published in Science.
“It’s like a farmer being able to grow crops in the desert or in Antarctica,” adds co-author Professor Huw Davies, a chemist at Emory University, USA.
“It opens the possibility for synthesising materials that are completely different from anything we’ve known.”
For now, the team has made a molecule called (-)-cylindrocyclophane A. The compound naturally occurs in blue-green algae bacteria.
While chemists have made the molecule in the lab before, they’ve always used complicated molecular precursors to achieve its convoluted, asymmetric cylindrical structure.
This team made the molecule with much simpler starting points, manipulating 10 C-H bonds at precise points to get the shape they wanted.
To do this, they used several catalysts, based on the precious metals rhodium and palladium.
“I think this paper shows that you can use these very selective, very interesting, and very unusual transformations even in a complex setting,” says Stoltz.
“It’s exciting that you can think of a very new way to break bonds,” says co-author Camila Suarez, a graduate student at California Institute of Technology.
“New reactions are being developed every single day, and they’re becoming more robust, more powerful, more selective for very unusual and interesting transformations.
“Because of this innovation, we’re able to think of new ways to synthesise natural products, and I feel like that’s really important because organic chemistry is such a fundamental science that is involved in so many other sciences.”
