Transformations of Aryl Ketones via Ligand Promoted C–C Bond Activation

Coupling of aromatic electrophiles (aryl halides, aryl ethers, aryl acids, aryl nitriles etc.) with nucleophiles is core methodology for the synthesis of aryl compounds. Transformations of aryl ketones in analogous manner via carbon-carbon bond activation could greatly expand the tool-box of the synthesis of aryl compounds due to the abundance of aryl ketones. Exploratory study of this approach is typically based on carbon-carbon cleavage triggered by ring-strain release and chelation assistance, and the products are also limited to a specific structural motif. Here we report a ligand promoted β -carbon elimination strategy to activate the carbon-carbon bond, which allows for the establishment of a range of transformations of aryl ketones, leading to useful aryl borates, and also to biaryls, aryl nitriles, aryl alkenes. The use of a pyridine-oxazoline ligand is crucial for this catalytic transformation. A gram scale borylation reaction from aryl ketone via a simple one-pot operation was occurred successfully. The potential utility of this strategy was also demonstrated by the late-stage diversification of drug molecules Probenecid, Adapalene and Desoxyestrone, spice Tonalid as well as natural product Apocyin.