Wiring up organic synthesis

For almost a century, terpene synthesis has been a yardstick against which synthetic organic chemists have measured the state of their art. The latest tilt at the terpenes, designed to come the closest yet to mimicking nature’s mastery, comes from the labs of Phil Baran at Scripps, and his collaborators. The chemical methods needed to perform the key decarboxylative reaction, however, proved far from ideal. An excess of harsh reagents, cryogenic temperatures, protecting groups and functional group interconversion steps were all required to achieve the transformation.

The project, at risk of flatlining, was revived by electrochemistry.

Thanks to some intra-lab cross-fertilisation, a mild, high-yielding electrochemical procedure, tolerant to different functional groups, for the key polyolefin precursor assembly step was developed. The route enabled the synthesis of not one, but 13, complex terpenes in notably few synthetic steps. The study is the latest of a rapidly growing list of examples in which electrochemistry efficiently brings about organic transformations that are otherwise either difficult or impossible to complete.