Ruthenium(II)‐Catalyzed CH Functionalizations with Allenes: Versatile Allenylations and Allylations

Ruthenium(II)‐catalyzed direct C?H functionalization of aromatic compounds with allenes was achieved under exceedingly mild reaction conditions to yield trisubstituted allenes. The reactions of N‐methoxybenzamides proceeded smoothly in an isohypsic fashion at ambient temperature with high chemo‐ and regioselectivity, thereby providing a versatile means of accessing trisubstituted allenes. Detailed mechanistic studies were suggestive of a kinetically relevant C?H metalation step, which occurs by the assistance of a carboxylate moiety; this also set the stage for unprecedented C?H allylations with removable directing groups in a step‐economical fashion.