Platinum-Catalyzed Double Acylation of 2-(Aryloxy)pyridines via Direct C-H Activation.

A unique, platinum-catalyzed, direct C-H acylation of 2-(aryloxy)pyridines with acyl chlorides is discovered. The reaction requires neither an oxidant nor other additives. When both ortho positions of the aryl group are accessible, the double acylation occurs readily to produce the diacylated products. Aliphatic, aromatic, and α,β-unsaturated acyl groups can all be introduced. The acylation reaction may proceed through an analogous aromatic electrophilic substitution triggered by the nucleophilic attack of the platinum at the acyl chloride.