Ligand‐Boosted Copper Catalysis for Air‐Tolerant Methoxylation of (Hetero)aryl Halides With Sodium Methoxide

ABSTRACT An air‐tolerant, simple yet highly efficient copper‐catalyzed methoxylation of (hetero)aryl bromides and some activated chlorides has been developed by using copper(II) chloride/2,2‐bipyridine as catalyst precursor. A wide range of (hetero)aryl bromides and electron‐deficient chlorides could be efficiently methoxylated in good to excellent yields at 1‐mol% catalyst loading albeit showing a functional group compatibility dependent on the electronic properties of aryl ring. Applications of the practical protocol have been demonstrated in multigram synthesis of 3,4,5‐trimethoxytoluene.