A team of chemists at The Scripps Research Institute (TSRI), La Jolla, CA, say that they have invented a new method to join complex organic molecules that is extraordinarily robust and can be used to make plastics, pharmaceuticals, fabrics, dyes, and other materials previously inaccessible to chemists.
“We are rewriting the rules for how one thinks about the reactivity of basic organic building blocks, and in doing so we’re allowing chemists to venture where none has gone before,” said Phil S. Baran, the Darlene Shiley Chair in Chemistry at TSRI, whose laboratory reported the finding.
With the new technique, scientists can join two olefins to create a new bond between their carbon-atom backbones. Carbon-to-carbon coupling methods are central to chemistry, but until now have been plagued by certain limitations: they often fail if either of the starting compounds contains small, reactive regions known as “functional groups” attached to their main structure. They also frequently don’t work well in the presence of “heteroatoms”—non-carbon atoms such as nitrogen, oxygen and iodine—despite the importance of these types of atoms in chemical synthesis.
The new method is what chemists call “mild,” meaning that it doesn’t require the use of extreme temperatures or pressures, nor harsh chemicals. As a result, portions of the building blocks used that are particularly fragile remain unaltered by the reaction.
They say that the reaction setup is easy, using a simple iron catalyst, a commercially available silane, and ethanol as the solvent. And, the reaction can be done in an open flask.
In their report, the researchers described making more than 60 compounds with the new method, with around 90 percent of them being new chemical entities.