Palladium-Catalyzed C−H Iodination of Arenes by Means of Sulfinyl Directing Groups

C−H iodination of aromatic compounds has been accomplished with the aid of sulfinyl directing groups under palladium catalysis. The reaction proceeds selectively at the peri-position of polycyclic aryl sulfoxides or at the ortho-position of phenyl sulfoxides. The iodination products can be further converted via iterative catalytic cross-coupling at the expense of the C−I and C−S bonds. Computational studies suggest that peri-C−H palladation would proceed via a non-directed pathway, wherein neither of the sulfur nor oxygen atom of the sulfinyl group coordinates to the palladium before and at the transition state.