Palladium(II)‐Catalyzed Selective Arylation of Tertiary C−H Bonds of Cyclobutylmethyl Ketones Using Transient Directing Groups

Abstract We report the first example of selective Pd II ‐catalyzed tertiary C−H activation of cyclobutylmethyl ketones using a transient directing group. An electron‐deficient 2‐pyridone ligand was identified as the optimal external ligand to enable tertiary C−H activation. A variety of cyclobutylmethyl ketones bearing quaternary carbon centers was readily accessed without preinstalling internal directing groups in up to 81 % yield and >95 : 5 regioisomeric ratios of tertiary C−H arylation to β‐methylene (β‐methyl) or γ‐C−H arylation.