LIGANDS ARE KEY TO CHIRALITY

Abstract

BY RELAYING chiral information from an amino acid ligand to a palladium catalyst and onward to a substrate, Jin-Quan Yu and colleagues at Scripps Research Institute have selectively functionalized carbon-hydrogen bonds to form optically pure products ( Angew. Chem. Int. Ed. , DOI: 10.1002/anie.200801030). This finding could reduce the number of steps needed to make molecules, one of the most coveted goals for synthetic chemists. Activating the relatively inert C-H bond enantioselectively and catalytically can already be achieved through several approaches, but none of these techniques involve formation of a chiral carbon-metal bond during the reaction. Yu’s team is the first to demonstrate this type of transformation by using a chiral palladium catalyst. Yu and coworkers sought ligands that would coordinate to Pd and influence the enantioselectivity of the catalyst insertion into C–H bonds. “You need to have a chiral environment as close as possible to the Pd metal center so Pd can transmit chiral informa...