Rhodium-catalyzed Intermolecular Ketone Hydroacylation: Towards an Enantioselective and Diastereoselective Protocol

The addition of an aldehyde C−H bond across a ketone functionality, formally a hydroacylation, has emerged as an atom-economical approach to the synthesis of esters. While this is an efficient strategy for producing biologically-relevant materials, the field of transition metal-catalyzed ketone hydroacylation is currently limited to intramolecular systems. The development of a new rhodium catalyst will be presented, and its application to intermolecular ketone hydroacylation will be discussed. Ester products were synthesized from unfunctionalized, aliphatic aldehydes and chelating ketones in excellent yields under relatively mild reaction conditions. Efforts towards an asymmetric intermolecular ketone hydroacylation will be described, including the application of known chiral catalysts and the development of novel chiral phosphine ligands for asymmetric catalysis. Ester products were obtained in as high as 78% enantiomeric excess.MAS