Tandem Catalysis: Access to Ketones from Aldehydes and Arylboronic Acids via Rhodium‐Catalyzed Addition/Oxidation

Direct cross‐coupling reactions of aromatic aldehydes with arylboronic acids afforded ketones in high yields and under mild conditions in the presence of a rhodium catalyst, acetone and a base. This new reaction, involving a formal aldehyde CH bond activation, is believed to proceed via a tandem process involving addition of the organometallic species to the aldehyde followed by oxidation by β‐hydride transfer.