Photoredox catalysis unleashes carbynes’ synthetic power

Abstract

Methylidyne, a carbon-based gas believed to have helped form the first molecules of life and one of the earliest molecules ever discovered among the stars, belongs to an unusual class of compounds called carbynes. These highly reactive compounds are not to be confused with the contentiously categorized, one-dimensional string of carbons of the same name or with the more familiar carbenes. Carbynes, according to organic chemistry’s definition, are monovalent carbon species with three nonbonded electrons. These species have tantalized researchers with the prospect of forming three new bonds from a single atom, but synthetic chemists have been unable to tame these unruly molecules. A team led by Marcos G. Suero at the Institute of Chemical Research of Catalonia has developed a new method that sidesteps carbynes’ unstable nature by generating their molecular equivalent, a diazomethyl radical species, using photoredox catalysis (Nature 2018, DOI: 10.1038/nature25185). The researchers can install these radical