David Nicewicz and David MacMillan at Princeton University in New Jersey created a double-headed catalytic system to give an aldehyde molecule an alkyl group in a specific position, and with a specific geometry.
Their technique depends on a pincer movement. A ruthenium-based 'photoredox' catalyst that shifts electrons one at a time when hit with fluorescent light is one prong; an organocatalyst developed to move single electrons is the other.
The light-activated ruthenium catalyst creates an alkyl halide radical; the aldehyde is dealt with by the organocatalyst; and the reactants are brought together with precision so as to give most of the product the desired handedness. The reaction is easy to perform and broadly applicable, say the authors, and will make life easier for those developing new drugs.