Oxygen Electrophile‐Enabled Nickel‐Catalyzed Carboalkoxylation of Biphenylene CC σ‐Bond

A nickel‐catalyzed carboalkoxylation of the biphenylene CC σ‐bond with arylboronates and peroxides has been developed to form the corresponding ring‐opening difunctionalization products. The key to success is the use of acetal‐based, electron‐deficient peroxides, which enable the otherwise challenging CO cross coupling with nickel catalysts even under thermal conditions. A similar nickel catalysis is applicable to a related borylalkoxylation by replacement of arylboronates with danB–Bpin.