An enantioselective synthesis of 2-aryl cycloalkanones by Sc-catalyzed carbon insertion.

Current methods for asymmetric α-arylation require blocking groups to prevent reaction at the α'-carbon, basic conditions that promote racemization, or multistep synthesis. This work records the first catalytic enantioselective examples of the diazoalkane-carbonyl homologation reaction. Medium ring 2-aryl ketones are prepared in one step in up to 98:2 er and 99% yield from the unsubstituted lower homologue by Sc-catalyzed aryldiazomethyl insertion with simple bis- and tris(oxazoline) ligands.